The midfielder has hailed coach Jupp Heynckes' tactical plan in Tuesday evening's encounter in Munich
Thomas Muller gave Bayern the lead in the first half, before Mario Gomez, again Muller and Arjen Robben put the match to bed after the interval and Schweinsteiger was pleased to see that their game-plan paid off.
"We tried to put them under pressure and we succeeded," Schweinsteiger was quoted as saying on the official Bayern website.
"At the start, it was a steep learning curve, because we've never played against a team with this kind of game-plan.
"We did our job better and better as time went on. We invested a lot of effort and it's great we were rewarded."
The second leg at Camp Nou will take place on May 1.