Arsenal and Chelsea meet at the Emirates Stadium on Saturday evening in a London derby that could prove pivotal to the outcome of both club's seasons. Six points currently separate fourth-placed Chelsea from fifth-placed Arsenal but both will be acutely aware of the colossal difference - both financially and in terms of prestige - between those two positions come May. With both forced to watch their rivals jealously from the backwater of the UEFA Europa League this season, they certainly don't want to make a habit of playing in the continent's secondary competition. Unai Emery (left) and Maurizio Sarri (right) will go head-to-head when Arsenal play Chelsea in the Premier League on Saturday evening With Chelsea six points ahead of Arsenal in fourth place, Saturday's game will be crucial In many ways, Chelsea and Arsenal are on parallel tracks this season having appointed new managers - Maurizio Sarri and Unai Emery respectively - back in the summer. Both bosses brought fresh approaches to doing things as they embarked upon their first seasons in English football. But the results have been mixed. Sportsmail analyses how the two coaches have fared this season so far in different departments. RESULTS AND FORM Unai Emery: In terms of endearing yourself to the fans of a new club, embarking on a 22-match unbeaten run, including 17 wins, isn't a bad way to go about it. That's precisely what Emery's Arsenal did after defeats to Manchester City and Chelsea in two fiendish opening fixtures in English football for the Spaniard. The highlight of the sequence was a thriling 4-2 home win over bitter rivals Tottenham, while there was evidence of a new-found resolve when they came from behind to hold title-chasing Liverpool. There were also a number of free-scoring displays that had the fans chanting 'We've got our Arsenal back' following the inertia of the last few years under Arsene Wenger. Arsenal's 4-2 win over Tottenham in the north London derby in December was a highlight so far But if it all seemed too good to be true, it was. Things very quickly unravelled for Arsenal over the festive period as their unbeaten streak was snapped at Southampton. That was swiftly followed by a Carabao Cup exit as Spurs exacted revenge and then a 5-1 drubbing at Liverpool in which their creaking defence was torn apart time after time. Last weekend's 1-0 loss at West Ham, where Arsenal were out-muscled and out-worked, left them trailing Chelsea by six points in the race for the Champions League. Pierre-Emerick Aubameyang (right) and Mateo Guendouzi react during the loss to West Ham Maurizio Sarri: The Italian was new to English football but you wouldn't have known it by the storming start Chelsea made to the season. Wasting little time in introducing his attack-minded and attractive brand of football, Sarri's side remained unbeaten in 18 matches from the opening day of the league season until a 3-1 loss at Tottenham on November 24. There were some highly promising performances in there, such as the early season 3-2 win over Arsenal, the 2-1 win at Liverpool in the Carabao Cup and the home draw against Jurgen Klopp's team where they led until the final minute. Chelsea celebrations after Alvaro Morata scores in their 3-2 win over Arsenal in August But Spurs were the first opponent to really figure Sarri out and since then it's been something of a mixed bag as Chelsea dropped out of title contention. While there have been highs, such as a 2-0 home win over reigning champions Manchester City, there have also been demoralising losses to Wolves and Leicester City, plus a drab goalless draw at home to Southampton. Few of Chelsea's victories have been achieved in swashbuckling style, often coming by virtue of a single goal, and plenty of questions remain about their goal shortage. David Luiz ends up in the net after missing a great chance in Chelsea's defeat to Leicester STYLE OF PLAY Unai Emery: One of the major gripes about the decaying Arsenal team under Arsene Wenger was a lack of resilience and leadership that often caused them to lose matches they shouldn't be losing. Another was a lack of finishing following their often elaborate build-up in and around opposition penalty areas. With the signing of Uruguayan hardman Lucas Torreira and, to a lesser extent, the young and hard-working Matteo Guendouzi, Arsenal certainly look liable to capitulate in midfield. And with Pierre-Emerick Aubameyang and Alexandre Lacazette both enjoying prolific seasons, scoring 25 times between them, there has been a better end product as well. Pierre-Emerick Aubameyang is enjoying a fine season, scoring 16 times so far for Arsenal But then everything tends to look good during a long unbeaten run. Recent results and performances have exposed new and worrying deficiencies. The defensive line looks ageing and brittle, even when three centre-backs are deployed in Emery's 3-4-3, with none of them capable of bringing the ball out. Some recent games have seen a shortage of creativity as well, leading to questions over Emery's decision to allow Aaron Ramsey to leave and sideline Mesut Ozil. Though two of Arsenal's best advanced midfielders, neither seems to be in Emery's favour and that creates a flaw in the 4-2-3-1 system he is likely to revert to against Chelsea. Emery has decided to omit star man Mesut Ozil from a number of recent matches Maurizio Sarri: We awaited the arrival of 'Sarri-ball' into the Premier League with relish back in the summer, it was a cool experiment like a chemistry teacher demonstrating how the Bunsen burners worked for the first time. And initially it was a whole lot of fun - witness the reverse fixture between these two teams in August: Chelsea won 3-2 but Arsenal had enough chances to win 6-3 themselves. 'Sarri-ball' was a notion known to Italian football aficionados from Sarri's time with Napoli but relatively unknown to most in the Premier League. The metronomic passing and diagonal balls went predominantly through Jorginho, the £50million summer arrival who understood 'Sarri-ball' so well it was like he'd been brainwashed by a cult. Maurizio Sarri was insistent Chelsea sign Jorginho from his former club Napoli But while Jorginho set all kinds of new passing stat records - he needs three more to surpass 2,000 in the Premier League this season - opponents worked out you just needed to mark him to stop 'Sarri-ball' in its tracks. Everton and Tottenham were among the first to do this in November, setting a man-marking trap for Jorginho, and the template was set for the rest of the division's managers. The number of passes per game dropped once this happened and the goals dried up in a worrying manner. Sarri isn't too keen on strikers Alvaro Morata or Olivier Giroud, often preferring to play Eden Haxard as a false nine, and their urgent need for a new striker is very much apparent. The Italian needs to prove there is a 'Sarri-ball 2.0' if Chelsea are to make any strides under his leadership. With Sarri not really trusting his strikers, Eden Hazard has been playing the false nine role TRANSFER BUSINESS Unai Emery: After the incoming Emery identified his summer targets nice and early, Arsenal's transfer business was conducted smoothly and with the minimum of fuss. Torreira, who cost £26.4m from Sampdoria, has quickly become a fan favourite while 19-year-old Guendouzi, signed for £7m from French club Lorient, has hit the ground running impressively quickly. Sokratis, £17.7m from Borussia Dortmund, has added steel to the back line, performing well on the whole while veteran right-back Stephan Lichtsteiner has been used more sparingly. While the summer was relatively busy and Emery's additions generally positive, the manager is downbeat about Arsenal's chances of signing anyone this month. Lucas Torreira, who signed from Sampdoria for £26.4m, has added steel to the midfield He wants to secure Barcelona midfielder Denis Suarez on loan but the uncertainty over the future of the club's head of recruitment Sven Mislintat isn't helping matters. It is believed Mislintat feels too many of his grand plans to transform the behind-the-scenes workings at Arsenal have been blocked. With Arsenal's squad clearly nowhere near strong enough to challenge for the title at the moment, it will be intriguing to see how this internal power struggle plays out. Until it does, there doesn't appear much prospect of new signings coming in. Perhaps Wenger, in seeking to wield absolute authority over all facets of the club, was on to something after all. Another complication to come is over Ozil, who clearly isn't trusted by Emery yet whose wage demands put him beyond the reach of any suitors. Barcelona midfielder Denis Suarez is Arsenal's No 1 transfer target for the January window Maurizio Sarri: As previously mentioned, Jorginho was the one man Sarri pretty much insisted on when he rocked up at Stamford Bridge back in the summer. Chelsea also needed a new top-class goalkeeper with Thibaut Courtois forcing his way out of the club to join Real Madrid. They willingly broke the transfer record for a keeper to sign Kepa for £72m from Athletic Bilbao and the Spaniard has performed well enough so far. With one eye on the future, Chelsea have already sealed the signing of exciting American international Christian Pulisic from Borussia Dortmund, paying £58m for the exciting playmaker. Kepa, signed for a record £72m fee from Athletic Bilbao, has made a good start to Chelsea life But he will have to wait until next season because right now Chelsea are in desperate need of goals and a world class striker who can provide them. That's why Sarri has moved for Gonzalo Higuain, with whom he worked in his first season in charge of Napoli. The deal is on the verge of being completed. The Argentine has reliably scored goals throughout his career and enjoyed the best season of his career when he scored 38 goals in Sarri's system at Napoli. It remains to be seen whether he can power Chelsea to a strong finish to the season as they continue to compete on four fronts. Gonzalo Higuain looks to be Chelsea bound following a loan spell at AC Milan from Juventus POPULARITY AND PERSONALITY Unai Emery: Arsenal's new manager insisted on holding his first press conference in fractured English endeared him to a fair few people as he slowly tried to explain his philosophy in a new language. He later admitted to watching Peaky Blinders to help him perfect his English skills, which may not be the best idea! Emery cuts a highly animated figure on the touchline, rarely sitting down during games and making all manner of gestures to encourage his players. There has been one brush with the authorities after he accidentally booted a water bottle into the stands at Brighton last month. He apologised to all concerned immediately but was still fined £8,000 by the FA. Emery shows no shortage of emotion on the touchline, often gesticulating wildly His insistence on putting his players through hours of video analysis hasn't grated too much so far and he takes a proactive approach on the training ground. For Arsenal fans, Emery was always going to be given patience and time after so many years of stagnation under Wenger. And there have been clear signs of improvement, especially in big games. Emery may need to be diplomatic in the months to come to ensure the Ozil situation doesn't lead to friction within the dressing room, especially if he continues not to play him. This season can still be a successful one if they push Chelsea hard in pursuit of fourth place and last the distance in the Europa League. Maurizio Sarri: Chelsea chop and change managers constantly so it can be hard for those in charge to gradually implement their philosophy while still getting results. Sarri's approach and way of doing things has certainly made things interesting for the fans this season, but the jury remains out. There's a nice charm about the workaholic Italian, who abides by old superstitions and spends each 90 minutes craving nicotine. He has his moments of annoyance on the touchline but so far hasn't stepped over the mark. Sarri very diplomatically defused the tension when his coach, Marco Ianni, taunted Man United boss Jose Mourinho after a late equaliser in October. Sarri pictured on the sidelines - the Italian knows he is under pressure to deliver at Chelsea One thing he is clearly not a fan of is the Video Assistant Referee (VAR), making his feelings plain after the defeat to Spurs in the Carabao Cup semi-final. Whether he remains in the Premier League to see VAR in operation week-in, week-out remains to be seen but this season can still be an encouraging one. If Higuain solves their goal drought, there's no reason why Chelsea can't finish in the top four and win one of the cup competitions. Getting back into the Champions League is going to be the main objective though. All rights reserved for this news site dailymail and under his responsibility