United's UEFA Champions League quarter-final tie is evenly poised after Tuesday's 1-1 draw at Old Trafford.
The result was a much-needed boost for United, who are set to relinquish their Premier League crown following a disappointing season on all fronts.
But David Moyes' men have the opportunity to salvage something from their disastrous campaign when they travel to Munich for the return leg on April 9.
Though Rooney concedes United must exceed their Champions League triumph in 2008 if they are to advance to the semi-finals of Europe's elite club competition.
"I think it would be our biggest performance in Europe in my memory if we went there and got a result," Rooney said.
"They are favourites for the tournament, and it will be a tough ask.
"We needed to give ourselves a chance, and still be in the tie - and we’ve done that.
"We have to focus on the return game and make sure we put everything into it. It’s a massive game for our season so we have to make sure we are ready."
Pep Guardiola's Bayern have swept all before them yet again this season as they retained the Bundesliga title.
The defending European champions are unbeaten at Allianz Arena in their past six games in all competitions but will be without the services of suspended duo Bastian Schweinsteiger and Javi Martinez.
United will take heart from Manchester City's 3-2 victory in the German city in December last year and the fact Bayern have conceded in each of their past four games on home soil.
"We have to go there and score," he said. "We're in the game. It's 50-50, and you can see we will get chances against them.
"They play a high line and with a little more composure, we can exploit that. We're still in the tie and looking forward to it.
"It will be tough and we have to defend well. We know they will have a lot of possession and we accept that. We must defend well and try and hit them on the break."
