We are midway through the Champions League group stages for the 2020-21 campaign and there are plenty of talking points as we enter into more midweek action.
Premier League clubs Manchester United and Chelsea could take huge steps towards the knockout stages as Liverpool continue to deal with their injury crisis, whilst reigning champions Bayern Munich could re-write the history books and Barcelona will have a rather noticeable absentee.
Here, Sportsmail looks at 10 talking points ahead of this week's Champions League action.
We are midway through the Champions League group stages for the 2020-21 campaign, and Real Madrid and Inter Milan will contest this week's most eagerly-awaited match-upInsurance Loans Mortgage Attorney Credit Lawyer
Messi missing for Barcelona
Lionel Messi has been left out of the Barcelona squad to face Dynamo Kiev on Tuesday after one of his worst performances for the club in Saturday's defeat by Atletico Madrid.
Whilst the omission of Messi could be a sign of further distress between him and the club, manager Ronald Koeman cited the reasoning for leaving him and midfielder Frenkie De Jong out is due to their comfortable position in the group.
Barcelona are top of Group G, seven points ahead of third-placed Kiev so allowing Messi to rest makes sense on the surface, but add more context and Barca fans could be getting a taste into the near future as Messi continues to be linked with a move away.
The Argentine has not looked himself this season. He lost the ball an astonishing 23 times in the 1-0 defeat at the Wanda Metropolitano. He also managed just 36 passes.
Lionel Messi gave one of his worst performances for Barcelona in Saturday's defeat by Atletico Madrid, and he will now sit out their Champions League clash with Dynamo Kiev
Four-goal Haaland on fire
Borussia Dortmund frontman Erling Haaland continues to prove why he is one of the most sought-after strikers in the world following his Golden Boy award triumph, naming him as Europe's best player under the age of 21.
The Norway international, 20, currently leads the Champions League golden boot race alongside Liverpool's Diogo Jota, Juventus striker Alvaro Morata and Manchester United's Marcus Rashford.Insurance Loans Mortgage Attorney Credit Lawyer
He will likely lead the line as Dortmund play host to Club Brugge after he scored an incredible four goals in 22 minutes against Hertha Berlin on the weekend.
Erling Haaland scored four goals in 22 minutes against Hertha Berlin on the weekend
Manchester United's revenge mission
Ole Gunnar Solskjaer's most recent memory of the Champions League will be one of his worst since he took over as Manchester United manager.
The Red Devils host Istanbul Basaksehir on Tuesday and revenge must be on the agenda. United suffered a shock 2-1 defeat by the Turkish side in the reverse fixture and Demba Ba's opener highlighted their shambolic defensive organisation.
It's still all to play for in Group H with United and RB Leipzig on six points but not far behind them are Basaksehir and last year's finalists Paris Saint-Germain on three points.
Chelsea can secure progress
Frank Lampard can lead his side to the knockout stages of the Champions League should they beat Rennes and Sevilla win against Krasnodar in Group E's other match-up.
The Blues are starting to find their feet under Lampard with all their new summer additions having had a little more time on the training pitch.
Entering the match unbeaten in nine matches across all competitions and with five straight victories, including four clean sheets, Chelsea will want to assure their place in the next round as it will allow them to rest key players for the final two fixtures in the group as part of this season's hectic schedule.
Mason Mount (right) and Chelsea will want to assure their place in the next round this week
Who will play for injury-stricken Liverpool?
Jurgen Klopp finds himself at sixes and sevens trying to assemble a squad for the next few matches as Liverpool's injury crisis continues.
The Reds are without Trent Alexander-Arnold, Joe Gomez, Virgil van Dijk,