The final round of group matches in this season’s Champions League takes place on Wednesday.
Chelsea need a point against Porto in order to reach the knockout stage from Group G.
The Premier League champions have struggled domestically, losing eight of their 15 league games.
Despite enduring a disastrous campaign boss Jose Mourinho believes club owner Roman Abramovich will not sack him.
He said: “I don’t think the owner is a person to change with the wind. The owner knows who I am, the owner knows what I give to the club and the owner believes I am the right person to do the job.”
So the winner of the game will win the group – a draw will see Chelsea through in second. A win for Dynamo Kyiv against Maccabi will put them into last 16 for first time in 16 years.
Forward Alexis Sanchez and Spain midfielder Santi Cazorla are two of several key players missing for Arsenal, who take on the Greeks of Olympiakos in Piraeus.
The Gunners will qualify for the last 16 as Group F runners-up if they better their rival’s 3-2 win from the reverse fixture.
That result or better would give Arsene Wenger’s side a better head-to-head record than Olympiakos and send them through.
Elsewhere it’s a dead rubber in Croatia as Group winners Bayern Munich, whose unbeaten start to the Bundesliga was ended at the weekend, take on eliminated Dinamo Zagreb.
Holders Barcelona already through as Group E winners. They finish off against Bayer Leverkusen, who along with Roma and Bate Borisov all have a chance of grabbing the runner’s up spot.
And finally in Group H, Gary Neville takes charge of his first game as coach of Valencia. The Spaniards will need to beat eliminated Lyon and hope Gent do not beat group winners Zenit to make last 16.