sport news How have Unai Emery and Maurizio Sarri fared in English football so far?  

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.

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.

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.

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.

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.

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.

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. 

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.

But

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