Bayern Munich overcame a two-goal first-leg deficit to Porto on Tuesday, hammering the Portuguese side 6-1 to book their place in the Champions League semifinals. It was the second straight knockout-round tie this season in which the German record champions rebounded after a lackluster first-leg performance to win at home in a rout—and it came as a timely reminder of just how devastatingly brilliant they can be when at their best.
Pep Guardiola's side looked markedly different in Tuesday's game compared to the previous week's performance and blitzed their visitors for five goals before half-time. Thiago Alcantara and Jerome Boateng erased their first-leg deficit within 22 minutes, and Robert Lewandowski scored on either side of a Thomas Muller strike before the interval. Jackson Martinez pulled one back for Porto after the break, but it was too little, too late. Xabi Alonso restored Bayern's five-goal advantage shortly before full-time with a brilliant free-kick, which really was just icing on the cake of a fine performance.
Even in the opening minutes, it was hard to imagine the Bayern side on the pitch on Tuesday was by and large the same that had been so badly beaten in Portugal. A week before, they made defensive mistakes that looked amateurish. Their play on the ball was predictable and far too narrow.
Guardiola made some key changes for the second leg, which markedly changed the tie. Dante, who'd been abysmal in the first leg, was dropped to the bench with Holger Badstuber his replacement. The key tactical change, though, was that in the second leg, Bayern used width to their advantage. In the first leg, their one goal (and only real chance) came from a rare attack down the wing and a cross from which Alcantara converted.
On Tuesday, Bayern were much more eager to use width to their advantage, especially exploiting the absence of Porto's first-choice full-backs, Danilo and Alex Sandro. Both of Lewandowski's goals, as well as Thiago's and Boateng's, came from crosses.
Guardiola was forced to leave his comfort zone in preparing for Tuesday's game, and not for the first time learned from his mistakes. He's always preferred a conservative approach, one based on control. That went too far away to Shakhtar, as Bayern hardly created a chance and were held scoreless whilst playing in the absence of a true centre-forward. He restored Lewandowski to the starting XI in the second leg, and the striker scored and gave two assists in a 7-0 rout.
In the second leg of the Porto tie, Bayern were unable to play conservatively: They had to go for it, needing at least two goals to advance. The five-time European champions played more aggressively and were much more direct. In that regard, and especially given their use of play on the wings, they looked much more like the side Jupp Heynckes led to the treble in 2012-13, playing to their strengths.
Since benching Lewandowski in the Shakhtar match, Guardiola hasn't repeated his mistake. He seems to have learned from the first leg against Porto, and if he continues to use his team as he did on Tuesday, they can go far.
As great as Bayern were on Tuesday, the one caveat is that they absolutely cannot afford another disaster away from home, a concern given that Guardiola's record in first-leg Champions League knockout ties away from home is unimpressive at 4-8-5. Even a scoreless draw is acceptable, but Porto were always limited, a vastly lesser side even than Bayern's depleted team that proved their quality in front of their home fans.
Bayern will undoubtedly face far more difficult opponents than Porto in the semifinals and (though the match will be played near home, in Berlin) won't have the home-field advantage should they reach the final. Still, if Guardiola uses his team to their strengths and gets the best out of them as he did on Tuesday, there's nothing that can stop them.