Zenit St. Petersburg and FC Porto remain in competition for the one remaining Champions League spot in Group G.
Porto, a two-time European champion, has the tougher task with a visit to group winner Atletico Madrid. Zenit travels to winless Austria Vienna, which will finish last in the group.
Here are five things to know about Wednesday's games:
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ON THE LINE
Either Zenit or Porto will advance to the knockout stages of the competition. The other will continue playing in the continent's second-tier competition, the Europa League.
Zenit can avoid returning to the Europa League, where it played last season after missing out on the last 16 by one point, by at least matching Porto's result.
Porto must beat Atletico and hope Zenit loses in Vienna to advance. If the teams finish tied on points, the Russians advance with a better head-to-head record.
Zenit finished one point ahead of Porto two seasons ago to put the Portuguese champions into the Europa League.
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LOOKING TO LUCHO
Porto's hopes of salvaging its Champions League campaign received a lift with the inclusion of Lucho Gonzalez in the squad travelling to Madrid.
The Argentine midfielder missed training on Sunday and Monday due to a right hamstring strain, but coach Paulo Fonseca said his key playmaker has a chance of recovery.
Porto is on its worst ever run in a competition it has contested 18 times. But although they is winless in three home games, the Portuguese champions are unbeaten on the road in Group G.
Fonseca said his team must take advantage of any chances in front of goal as striker Jackson Martinez did in scoring both goals in Saturday's 2-0 victory over Braga.
"Regarding the finishing, we have to improve that part of the game," Fonseca said.
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ATLETICO DOWN
Porto may be pleased to see that Atletico returns from Saturday's 4-0 Copa del Rey victory over Sant Andreu with some injury concerns.
The Spanish league co-leaders are likely to be without goalkeeper Thibaut Courtois, while forward Cristian Rodriguez was absent from training on Monday. Midfielder Mario Suarez continues to recover from a knee injury and fullback Juanfran Torres is suspended.
"We'll go out there looking to win the game from the start. That's how we're achieving the great results we have all season," Suarez said. "We want to be fighting to win all of the important competitions."
Atletico, which is even at the top of the Spanish standings with Barcelona, has won all nine of its league and Champions League matches at the Vicente Calderon Stadium this season.
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IN CONTROL
Zenit's slender advantage going into its match at Austria Vienna has left it in control of its fate.
Zenit has some momentum after defender Nicolas Lombaerts scored the late winner in a 2-1 victory over Ural in the Russian league. Zenit is even with Lokomotiv Moscow at the top of the championship ahead of the winter break.
"We managed to play a good match and created many chances in a hard time for the team," Zenit coach Luciano Spalletti said.
Zenit will be without injured midfielder Miguel Danny and striker Alexander Bujhariv.
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13-YEAR WAIT
Austria Vienna cannot avoid finishing last, but it does want to go out on a positive note. The team is looking for a first victory in the competition for an Austrian team in nearly 13 years.
Sturm Graz was the last Austrian victor — a 2-1 win at Panathinaikos in February 2001.
Since then, only Rapid Vienna has managed to qualify for the competition, only to lose all six of its group games in 2005-06.
Austria Vienna has scored only two goals, but it has still managed two draws despite the lack of firepower up front.
"Now that we've got our first points and our first goal, we want to leave the Champions League with a win," Austria Vienna coach Nenad Bjelica said.
Despite being already eliminated, nearly 37,000 tickets have been sold for the match, which will be played at the Ernst Happel Stadium instead of its usual 13,000-capacity Generali Arena.