London rivals Chelsea and Arsenal are set to lock horns in a midweek Premier League encounter at Stamford Bridge.The Gunners and Blues have etched their names into Premier League folklore having played out a host of memorable fixtures between them, including Robin van Persie's hat-trick in West London, Chelsea's 6-0 rout to mark Arsene Wenger's 1000th game in charge of the Gunners, and many more historic moments.Their most recent meeting was an explosive showdown at the Emirates, for which Mikel Arteta made a staggering six changes from their previous outing. The Spaniard's gamble paid off as Arsenal were imperious against Frank Lampard's Blues and won 3-1 on the night, bringing their seven-game winless run to an end.📺 Now playing on Twitter💽 Arsenal 3-1 Chelsea▶️ 🔘──────── 02:00#ARSCHE pic.twitter.com/xPQTIPcwPH— Arsenal (@Arsenal) December 26, 2020The tables have turned ahead of their upcoming fixture as Chelsea are arguably one of the best teams in Europe at the moment under Thomas Tuchel, and are into the finals of the UEFA Champions League and the FA Cup.The German has only seen his side lose twice in 25 games across all competitions since taking over from Lampard, and they've won 17 of them. Chelsea have conceded just 11 goals in this period, with five of them coming in one game against West Brom.Thomas Tuchel (3) has now won more Premier League games away to the 'Big Six' as Chelsea manager than Frank Lampard (2) did in his 1.5 seasons at the club.He's only been at the club for 103 days. 🤯 pic.twitter.com/4NN97nprzd— Squawka Football (@Squawka) May 8, 2021On the other hand, Arsenal are currently in ninth place in the table and have had a miserable, trophyless season after crashing out of the Europa League semi-finals at the hands of Unai Emery's Villarreal.On Wednesday, Arteta will be tasked with leading his side to Stamford Bridge to face an in-form Chelsea. Ahead of the game, here, we take a look at five key players to watch out for.#5 Kai Havertz | ChelseaChelsea v Fulham - Premier LeagueGerman superstar Kai Havertz didn't have the best of starts to life at Stamford Bridge. The Chelsea man took time to settle into life under Lampard and was also sidelined after contracting the COVID-19 virus earlier on. However, matters have changed drastically since Tuchel took over as the German attacker has looked much more devastating than he did at the start of the season.Playing as an inside forward off the right or centrally as a 'hybrid' as Tuchel calls him, Havertz has been in superb touch over the last few weeks. Although he doesn't have too many goals to show for, the 21-year-old has, more often than not, run the show in the final third. With the freedom Havertz has been given in the final third, the Gunners' defenders must be careful not to be dragged out of position.#4 Gabriel Martinelli | ArsenalVillareal CF v Arsenal - UEFA Europa League Semi Final Leg OneNot many knew of Gabriel Martinelli before he moved to the Emirates back in 2019. While the promising Brazilian had a respectable start to life at Arsenal, it was against Chelsea that the teenager announced himself on the big stage with a wonder-goal back in January 2020. he led a ten-man Arsenal's counter and sprinted 67 yards to score a goal that helped his side leave Stamford Bridge with a point.Fast forward to over a year later, and Martinelli's career hasn't progressed as much as he'd have hoped due to untimely injuries. However, the 19-year-old is still held in high regard by his club and manager.When Gabriel Martinelli ran the length of the pitch to score for Arsenal against Chelsea 🏃‍♂️💨 pic.twitter.com/tJQYcetDv4— Goal (@goal) April 4, 2020Martinelli will look to end his season strongly with a memorable display at Stamford Bridge, the same venue which saw him endear himself to the Gunners faithful with that stunning goal 14 months ago.Also read: 5 Best Premier League players outside the traditional top 6 clubs