It's a big day for Andre Villas-Boas' current team and his former one as well.

Chelsea's Portuguese manager is already on the hot seat just months into his first season at the helm, and the questions about his future will only get louder if the Blues can't knock off Valencia in Tuesday's UEFA Champions League group stage finale (Fox Soccer Channel, 2:45 p.m.). A failure to do so (or to secure a goalless draw) would see Chelsea fail to clinch a place in the knockout stage of the tournament, something that has become a given over the last number of years.

Villas-Boas' former club, Porto, is also in must-win mode against Zenit-St. Petersburg (2:45 p.m., FoxSoccer.tv/DirecTV), as anything less will see the Portuguese champions finish in third place and drop down to the UEFA Europa League knockout round.

Here's a closer look at the rest of Tuesday's UCL matches:

GROUP E

Bayer Leverkusen is in fine position but still needs a result against last-place Genk (2:45 pm., FoxSoccer.tv/DirecTV) to cement its place atop the group table. A slip-up would allow the Chelsea-Valencia winner to claim first place in the group, which would send the German side into a tougher knockout draw. Based on Genk's last showing, a 7-0 loss to Valencia, Leverkusen should feel good about its chances.

GROUP F

Arsenal has already wrapped up first place, so the Gunners will turn to a makeshift side for their match in Greece against Olympiakos (2:45 p.m., Fox Soccer Plus/FoxSoccer.tv/DirecTV). That's good news for the Greeks, who need a win and some help to make it to the knockout stage. They trail Marseille by one point for second place, but the French club must face Borussia Dortmund (2:45 p.m., FoxSoccer.tv/DirecTV) while knowing that a draw or loss could prevent it from moving on. Dortmund isn't entirely dead but needs a victory of at least four goals and an Arsenal victory to steal second place.

GROUP G

While Porto and Zenit duke it out for one of the group's places in the knockout stage, APOEL Nicosia is already through with a game to spare. The Cyprus-based club can put the finishing touches on winning the group with a victory over disappointing Shakhtar Donetsk (2:45 p.m., FoxSoccer.tv/DirecTV).

GROUP H

With first place in the group all sewn up, Barcelona is expected to trot a side featuring reserves and younger players for its match against BATE Borisov (Fox Deportes/FoxSoccer.tv/DirecTV). The match has meaning for BATE, which could sneak into the Europa League with a surprise victory and some help. It would need AC Milan, which also is already through and has nothing left to play for, to beat Viktoria Plzen (2:45 p.m., FoxSoccer.tv/DirecTV) to open the door for third place.

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Do you think Chelsea will ultimately make the knockout round? How do you see the rest of Tuesday's matches playing out?

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