Bayern Thomas Müller opened the scoring in the 25th minute, before Mario Gomez netted in the 49th, and former Chelsea winger Arjen Robben made it three by the 73rd minute, their dominance over their Catalan opposition found through power, pace and clinical finishing in the final third.
As Barcelona struggled to look like scoring and foraged for an away goal to take back to Spain to give them some glimmer of hope, Müller sealed the result – and most likely Bayern’s place in the final at Wembley next month – with his second goal in the 82nd minute.
As Bayern dominated, Barcelona, on the other hand, struggled to get a foothold in the game, with an out of sorts and less than 100% fit Lionel Messi subdued in a way rarely seen.
Barca now find themselves facing more than an uphill struggle to reverse the deficit when the second leg is played at Nou Camp next Wednesday.
No team has managed to come back from a four goal first leg deficit in the Champions League.