Just over three months after Liverpool lifted the Champions League trophy in Madrid, Europe’s greatest club competition is once again back to make mid-weeks that little bit more entertaining.
Europe’s best sides will be looking to wrestle the title away from Anfield, as along with the Reds they enter the competition’s group phase looking to seal a place in the last-16 heading into the new year.
Here Sportsmail looks at all 32 challengers this season identifying their key men, strengths, weaknesses and their chances of triumphing above all in the Istanbul final next May.
Sportsmail looks at all 32 European challengers this season identifying their key men
Champions League best: Winners x13 (1955–56, 1956–57, 1957–58, 1958–59, 1959–60, 1965–66, 1997–98, 1999–2000, 2001–02, 2013–14, 2015–16, 2016–17, 2017–18)
Key man: Eden Hazard
Manager: Zinedine Zidane
Strengths: European pedigree. There are no steps into the unknown for Real, whether it is trips to Anfield or the Nou Camp they are unlikely to be intimidated anywhere. Even for the younger stars breaking into to the squad, dressing room influences like Sergio Ramos, Luka Modric and the newly signed Eden Hazard will be huge.
Weaknesses: The post-Cristiano Ronaldo slump. Replacing arguably the world's best player was never an easy task, if at all possible, but the Portuguese's departure has taken a fear factor out of Madrid, as evidenced by the way Ajax waltzed into the Bernabeu last term and dumped the holders out with a 4-1 win.
Odds to win: 10/1
Real Madrid finally got their man when bidding for Eden Hazard throughout the summer
Champions League best: Semi-finals (1994-95)
Key man: Kylian Mbappe
Manager: Thomas Tuchel
Strengths: The front line. There is an embarrassing amount of riches in it. Mbappe is part of a devastating attack that could include Neymar (if he can take away his focus from fleeing Paris), Edinson Cavani, Mauro Icardi and Eric Choupo-Moting (don't laugh, Stoke fans!) who has scored three times in his first two games this term.
Weaknesses: The front line. A good example of how a strength can also be a weakness. No doubt the talent is there but good luck trying to construct a team with it. Neymar and Mbappe's relationship has been fragile, especially with the former desperate to leave. Meanwhile new signing Icardi joins from Inter Milan, who couldn't get him off their books quick enough. It's a negative dynamic that could spread in a dressing room.
Kylian Mbappe has heaps of pressure and expectation placed upon his shoulders
Champions League best: Semi-finals (1988-89)
Key man: Ryan Babel
Manager: Fatih Terim
Strengths: Home support will be massive for Galatasaray. There are not many more intimidating places to go if the locals get behind the team, and many sides have come unstuck on their trips to Istanbul. Remember this is the same team whose supporters once greeted Manchester United with a 'Welcome to hell' banner. The Turk Telecom Stadium can look like it especially with the enormous amount of red flares that get lit.
Weaknesses: It is another year of transition for the Turkish champions who for the third season in a row have lost their main goalscoring threat following the departures of Lukas Podolski, Bafetimbi Gomis, and Henry Onyekuru. It's hardly ideal preparation for a team hoping to make the knock-out stages for the first time since 2014.
Champions League best: Runners-up (1977-78)
Key man: Hans Vanaken
Manager: Philippe Clement
Strengths: When you are placed in a group along with giants like PSG and Real Madrid there is not much else you have in your pocket aside from hope. But the lack of expectation for Bruges to progress also means they can play without fear and that can raise performance levels of the likes of attacking midfielder Vanaken.
Weaknesses: No fear, plenty of hope and care-free football can only get you so far. On paper they are the weakest team in the group and the overall ability of the squad means they could be in for a tough few months. Simon Mignolet is going to have a busy six evenings or so in goal.
Club Brugges have been boosted by the arrival of Simon Mignolet from Liverpool this summer
Champions League best: Winners x5 (1973–74, 1974–75, 1975–76, 2000–01, 2012–13)
Key man: Philippe Coutinho
Manager: Niko Kovac
Strengths: Fresh legs have come in at Bayern and the arrival of Coutinho adds excitement to a team that was growing stale. It's got stronger at the back too with Lucas Hernandez a high profile £72million signing from Atletico Madrid to bolster what had started to look like a creaking defence.
Weaknesses: The fresh legs are in but it comes at the sacrifice of experience. 'Been there, done that' stars such as Franck Ribery and Arjen Robben left the club after a combined 22 years of service and it remains to be seen how that will affect them on European nights.
Robert Lewandowski of FC Bayern Munich celebrates scoring during a recent fixture
Champions League best: Runners-up (2018-19)
Key man: Harry Kane
Manager: Mauricio Pochettino
Strengths: They have more comebacks than a comedian. There were four separate occasions last term when Spurs' Champions League exit looked just a few minutes away from as early as the group stage (twice). Yet late goals (and a VAR call) rescued them on more than one occasion to keep them scraping through. Never write them off.
Weaknesses: They have more jokes than a comedian. Pochettino's five years at Tottenham has resulted in zero trophies and they've had plenty of chances to win one. Somehow, someway, Spurs capitulate when the chips are down whether it's choking in a title fight, choking in a domestic cup semi-final or choking inside the first minute of a Champions League final. In a word, it's simply known as 'Spursy.'
Harry Kane and Tottenham fell at the final hurdle last season in the Madrid final
Champions League best: Winners x1 (1990-91)
Key man: Marko Marin
Manager: Vladan Milojevic
Strengths: The Rajko Mitic Stadium, or the Marakana as it is also known in reference to the famous ground in Brazil, will prove crucial for Red Star. Belgrade can be an intimidating place for a visiting side, with even Liverpool coming unstuck there last season as they slumped to defeat. If Red Star bag plenty of home points they have a good shot of making the knock-out stages.
Weaknesses: Playing outside of Belgrade. Their trips away from home last term resulted in three matches ending in a 13-2 aggregate defeat. Granted they were against big sides in Liverpool, PSG and Napoli but it will have to improve if they wish to progress in the competition.
Teams will find Marko Marin hard to handle, in the hostile atmosphere of Red Star's stadium
Champions League best: Quarter-finals (1998-99)
Key man: Kostas Fortounis
Manager: Pedro Martins
Strengths: They are well into the European groove now. Entering the Champions League in the second qualifying round they have been competing since July and have knocked out Viktoria Plzen, Istanbul Basaksehir and Krasnodar with a combined aggregate score of 13-1.
Weaknesses: On paper, or maybe more of a betting slip, they are ranked as the weakest team in the competition. Progressing beyond the groups is not unknown territory, they did it in 2014, but then they were also dumped out by David Moyes' Manchester United...
Olympiacos have knocked out Viktoria Plzen, Istanbul Basaksehir and Krasnodar already
Champions League best: Semi-finals (2015-16)
Key man: Raheem Sterling
Manager: Pep Guardiola
Strengths: Sergio Aguero, Kevin de Bruyne, Raheem Sterling, David Silva, Bernardo Silva, Gabriel Jesus, Riyad Mahrez. It’s an incredible collection of attacking players at the Etihad Stadium. Scoring goals is not going to be a problem for a team bookies think are favourites to win the competition this term.
Weaknesses: Even with his injury record, the exit of club captain Vincent Kompany is sure to have an impact on the defence. The additional loss of Aymeric Laporte through injury for the group stage at least raises even more question marks over the back line. They also seem to have rather bad luck involving VAR calls going against them.
Odds: 7/2 (Fav)
Sergio Aguero will be called upon to score the goals to see City progress in Europe
Champions League best: N/A
Key man: Duvan Zapata
Manager: Gian Piero Gasperini
Strengths: There are no recognised stars in the team, but the sum of the parts has made them a difficult outfit to play against. Despite their inexperience they have a highly motivated side that has enough in them to trouble any side in the group. You don't finish above both Milan clubs over a course of a year without having something about you.
Weaknesses: Speaking of Milan, that's where the Champions League new boys will be playing their home games this term in Europe due to renovation work at the Gewiss Stadium. It will be a step into the unknown at the San Siro and teams like Tottenham and Arsenal have shown how leaving home for much bigger surroundings (i.e Wembley) does not always work out.
Duvan Zapata leads the way for Atalanta is a team short of big-name stars
Champions League best: Quarter-finals (2010-11)
Key man: Junior Moraes
Manager: Luis Castro
Strengths: There is some promising attacking talent in the Shakhtar ranks outside of goal machine Moraes, including Yevhen Konoplyanka. The one-time Liverpool and Tottenham target has been one of European football's biggest enigmas of the decade but he is back on the biggest stage and at 29-year-old is still a major threat.
Weaknesses: They have not played a home game for five years. Shakhtar are forced to play their home games in Kharkiv due to their ground, the Donbass Arena, being caught up in conflict involving Ukraine and Russia.
Junior Moraes is a key man for Shaktar Donetsk, who can be dangerous on their night
Champions League best: First round/Group stage (1982-83, 1993-94, 1998-99, 1999-00, 2011-12, 2012-13, 2015-16, 2016-17)
Key man: Dani Olmo
Manager: Nenad Bjelica
Strengths: They know how to develop a player in Zagreb. Some handy stars have come out the academy in recent times including Ballon D'or winner Luka Modric. Former Arsenal striker Eduardo and AC Milan great Zvonimir Boban have also come out the production line, so there is potential for a few unknown gems in their ranks.
Weaknesses: History. Their Champions League record has been nothing short of shambolic. They have won just one game in 24 group stage matches since the turn of the century (albeit against Arsenal) drawing another and losing the rest.
Dinamo Zagreb's Champions League record has been nothing short of shambolic
Champions League best: Winners x2 (1984-85, 1995-96)
Key man: Cristiano Ronaldo
Manager: Maurizio Sarri
Strengths: Juventus are not just a one-man team in Ronaldo. Juventus are a one-man team in Ronaldo. There is class throughout a squad bolstered by summer signings including the £68million arrival of defender Matthijs de Ligt from Ajax as well as the free transfer of Aaron Ramsey from Arsenal. Wise old heads including Leonardo Bonucci, Giorgio Chiellini and the returning Gianluigi Buffon ensure there is a range of healthy experience in the ranks.
Weaknesses: Massimiliano Allegri had installed his own methods across five years at the Allianz Stadium but his summer exit means Juve will have a change of playing style to a slightly more possession based manner under Sarri. It could take a while for the players to get used to - and maybe even the manager too who has to deploy Sarri-ball without having a Jorginho to play in it.
Juventus are desperate to win the trophy and will play around talisman Cristiano Ronaldo
Champions League best: Runners-up (1973–74, 2013–14, 2015–16)
Key man: Joao Felix
Manager: Diego Simeone
Strengths: Seeing out a game. Some teams struggle trying to defend a lead but Simeone's side have made it an art form over the years. There is arguably no better team in the world at killing a game and shutting down an opposition's attack than Atletico.
Weaknesses: Are there enough goals in the side if on a rare day the defence does creak? Diego Costa and Alvaro Morata are good strikers, and Felix is one of Europe’s most exciting youngsters. But their record is only as good as the service provided. Atletico simply had no answer when Cristiano Ronaldo danced through them last term and dumped them out in the last-16 with a hat-trick.
Wonderkid Joao Felix has already made a bright start to life with Atletico Madrid
Champions League best: Runners-up (2001-02)
Key man: Kai Havertz
Manager: Peter Bosz
Strengths: Even with the loss of key creative star Julian Brandt in the summer there are lots of players still at the club capable of unlocking a defence including Havertz (tracked by just about every top club in Europe,)Kevin Volland, Leon Bailey and Karim Bellarabi.
Weaknesses: Since winning the German equivalent of the FA Cup in the early 1990s they have fallen just short of winning multiple Bundesliga titles and lost a Champions League final in that time span too... What's German for 'Spursy'?
Kai Havertz is one of a number of young, talented players in an exciting Leverkusen side
Champions League best: Last-16 (2002-03, 2003-04)
Key man: Grzegorz Krychowiak
Manager: Yuri Semin
Strengths: There is good experience within the squad including German international defender Benedikt Howedes, Euro 2016 star Krychowiak (honestly West Brom fans, he is a talent) former Tottenham star Vedran Corluka, Champions League regular Jefferson Farfan and even the match winner in a European