There were pre-match concerns that Bayern Munich would brush Man United aside at Old Trafford, but despite a tense opening 20 minutes the Red Devils held their own against Europe's most feared side.
Here, we take a look at why Man United have reason to be optimistic and travel to Germany to face Bayern Munich in the second leg full of optimism rather than self-doubt.
Old Trafford heart
A string of sub-standard results this season against the likes of Swansea, Everton and Newcastle at home has seen Old Trafford lose its fear factor of previous years.
However, on Tuesday night United showed the sort of desire and spirit which has been missing for large chunks of this campaign.
Manager David Moyes would have been particularly pleased with the performance of Danny Welbeck, who worked tirelessly before being substituted.
With Welbeck and Antonio Valencia occupying the wide positions, United seemed less rigid than when they lost to Liverpool and Manchester City at home recently.
Ryan Giggs pulled the strings in midfield throughout the first half, whilst the defensive partnership of Rio Ferdinand and Nemanja Vidic looked considerably stronger.
Moyes has struggled to accommodate Wayne Rooney, Robin van Persie and Juan Mata in his starting line-up, with the latter often being pushed out wide.
Mata's ineligibility for United in the Champions League looks to be a blessing in disguise, as the team's cohesion appears to improve in the absence of the Spanish playmaker.
English enjoy Allianz Arena
The record of the last four English teams to visit the Allianz Arena reads won three drawn one, meaning recent history is firmly in United's favour.
Moyes' side can take inspiration from the likes of Arsenal and Manchester City who managed to contain Bayern - as well as showing a clear attacking intent - while Chelsea, of course, won the 2012 Champions League final against Bayern on their own turf.
Psychologically it could affect Bayern if United score early in the match
Bayern have a particular problem in central defence after Javi Martinez picked up a yellow card, ruling him out of the second leg.
They do have a defender in the form of Daniel van Buyten on the bench, however, the Belgian international has only played 10 games this season and at the age of 36, may struggle to cope with United's pace in attack.
Bastian Schweinsteiger is easier to replace in midfield with the likes of Mario Gotze and Xherdan Shaqiri, but the vice-captain's experience on the pitch will surely be missed on such a big occasion.
Pep-ped at the post
Bayern boss Pep Guardiola suffered Champions League heartbreak in 2010 when his Barcelona team were clear favourites to progress against Jose Mourinho's Inter Milan, despite a 3-1 first-leg deficit.
Guardiola was also left scratching his head in 2012 when 10-man Chelsea knocked out his side after only having 27 per cent of possession in the Nou Camp.
United may try and adopt a similar approach which has got the better of Guardiola in the past.