After last weeks' 1-1 home draw, United go into tonight's crunch Champions League quarter-final second leg at the Allianz Arena still firmly in the tie.
Bayern's away goal means the job is probably not even half done and David Moyes' men face a tough task to progress. But if they can come out on top in these battles, they might just win the war.
Mario Mandzukic v Nemanja Vidic
Mandzukic was left out of the Bayern starting line-up at Old Trafford, with manager Pep Guardiola preferring to use Thomas Muller as a `false nine.`
Mandzukic will cause United's central defensive pairing of Vidic and Rio Ferdinand a different problem to the one they faced eight days ago. He caused havoc following his 63rd-minute introduction in the first leg and it was from his knockdown that Bastian Schweinsteiger scored Bayern's equalising goal.
The striker is expected to return to the team tonight and he will be keen to impress with his place about to come under threat from Robert Lewandowsk, who will join the German champions from Borussia Dortmund in the summer.
Mandzukic and Vidic exchanged words during the first leg when the United defender felt he had been elbowed during an aerial challenge. Progress to the next round would be the perfect retribution for Vidic as he looks to end his final season as a Red with a trophy.
Thomas Muller v Michael Carrick
Mandzukic's return and Schweinsteiger's absence through suspension is likely to mean Muller will drop back into that number 10 slot.
Muller can switch seemlessly into any attacking roles but playing behind a main striker is probably where he is best and most effective, with his positioning presenting problems for Vidic and Ferdinand. It will be Carrick's resposibility to pick him up and stifle his creativity.
Carrick did a similar job very well in the first leg as Toni Kroos' attempts to direct play were mainly done in font of the United defensive unit and at arm's length.
When his team have the ball, which may not be all that often tonight, Carrick can be relied upon to keep it, even if his distribution is more backwards and sideways rather than defence-splitting and penetrating. But Muller's work rate means the United midfielder will not be afforded much time to make his decisions.
Jerome Boateng v Wayne Rooney
Rooney is pivotal to United's chances at the Allianz Arena and the England striker, aided by a pain-killing injection, looks set to win his fitness battle after suffering a toe injury during the first leg.
With Robin van Persie out injured and Juan Mata ineligible, Rooney will be the main focus of the attack for Moyes' team. His tendancy to drop deep will cause Boateng problems by allowing the likes of Antonio Valencia and Danny Welbeck to try and exploit the space behind the Bayern defence. Welbeck did this brillaintly at Old Trafford from his side position.
Guardiola showered praise on Rooney at his pre-match press conference ahead of tonight's game, describing him as one of the best forwards he had ever seen, and Boateng will not have the comfort of his usual central defensive partner Javi Martinez alongside him as the Spaniard is suspended.
Arjen Robben v Patrice Evra
Evra is back from a ban and should return to the starting XI in Bavaria.
Alex Buttner deputised at left-back in the first leg but on a night when experienced heads are required, Evra will be tasked with stopping Robben.
Robben's pace and trickery were evident last week as his probing around the penalty area often made it a tense and nervy evening for United fans and players alike. But Evra is well equipped to match the flying Dutchman for speed and will also ask questions of Bayern going forward, with his opponent not particularly noted for always carrying out his defensive duties.