Lewandowski strruck twice, with Lamine Yamal and Raphinha also scoring in the second-half on Saturday night.
The Pole said afterwards: "We are very happy, very pleased. Winning here like this is a great victory. Not just today, but also other days. Now was when we had to win. Now we will be able to enjoy a few days. The season is long, but this victory can help us with much more, with confidence and football.
"The season is long and so far we have not won anything, but the important thing is that we have a clear idea, we know where we want to go. I think that as a team we play very well, offensively, defensively... We all go in one direction and that makes it easier to score goals.
"I always try to do my job, if I am closer to the area, it is easier for me. How we play is very important. I think that every coach has an idea. In my first season we won titles, and sometimes the results do not come. But this season we know where to go and in the end we have to continue with the same idea. So far we enjoyed this victory, but in two days we have another match..."