Manchester City boss Manuel Pellegrini faces one of the toughest team selections of his Etihad reign when his team take on Bayern Munich on Tuesday night.
When City kick-off against runaway group E leaders Bayern, they could do so in the knowledge that only a win will keep their hopes of progression alive.
With second place Roma taking on CSKA Moscow in a 5pm kick off, the Premier League champions face being five points adrift of their Italian rivals by the time their match with Bayern gets underway.
If the pressure of the fixture didn't make Pellegrini's team selection hard enough, he has a host of injuries and suspensions to contend with.
Pellegrini will be without star men Yaya Toure, suspension, and David Silva, injury, for what could be his biggest match since taking over from Roberto Mancini.
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Toure and his fellow midfielder Fernandinho have both been ruled out of the visit of Bayern having picked up red cards in the 2-1 defeat to CSKA last time out.
Their absence leaves Pellegrini with just five fit midfielders, with a possibility of all of them being fielded on Tuesday night.
Jesus Navas and Samir Nasri could be used out wide with James Milner, Frank Lampard and Fernando taking up central positions to attempt to contain Bayern's hugely talented midfield.
The German giants will no doubt dominate possession, meaning City's midfield could face a busy night chasing shadows should they opt for just four midfielders.
The concern for Pellegrini is that if he starts all five available midfielders, he has nothing to come off the bench should he need to freshen things up.
City will also be without injuried trio Silva, Edin Dzeko and Aleksandar Kolarov, as they take on one of Europe's in-form teams.
The Spanish attacker has failed to recover from a knee injury that has kept him out of the last four games, while Dzeko and Kolarov are some way from fitness.
Should Pellegrini opt to field a five-man midfield, striker Sergio Aguero will be left to lead the line alone against a Bayern team likely to contain ex-City defender Jerome Boateng.
Although the Argentine's game isn't exactly suited to playing as a lone striker, his goalscoring form this season, and Dzeko's injury, makes him the only real contender to start up top.
If City do manage to create chances, they can bank on Aguero to take more than he misses, and that'll be key against a Bayern outfit who give little away at the back.
While Aguero's form may be cause for concern for Pep Guardiola's defence, City must be alarmed by Bayern's form this season, especially in Europe.
The 2013 winners have won all four of their Champions League ties this season, including a 7-1 win in Rome.
If Aguero's form this season will scare Bayern Munich, City's defensive frailties this season will delight Robert Lewandowski and co.
Even the normally dependable Vincent Kompany has looked shaky, and having only just returned from injury he's unlikely to be at full fitness on Tuesday.
Partnering him is likely to be ex-Bayern man Martin Demichelis, who was given the nod ahead of Eliaquim Mangala for the weekend win over Swansea.
Pablo Zabaleta is likely to take his usual place at right-back, while Kolarov's injury means Gael Clichy will again start at left-back.
Predicted line up
Hart; Zabaleta, Kompany, Demichelis, Clichy; Navas, Milner, Fernando, Lampard, Nasri; Aguero