Despite having goalkeeper Wojciech Szczesny sent off on 55 minutes, Barca won 5-2 on Sunday night.
Lewandowski was on the scoresheet and began with the conversation he had with president Joan Laporta at the end of the match: "He congratulated me and said that we played very well in the first half. We played very well in the first half and the last 30 minutes with one man less were more difficult, but if you win 1-5 or 2-5 you have to be in control.
"A match against Real is always a vibrant match and it is even more so in a final. The important thing is how we want to play now or in the future. We always want more and today we knew that if we scored more goals than Real, we would win the title. We are very happy, but in three days we will have another match. Today we can enjoy ourselves, but from tomorrow we will prepare for the next challenge."
On Barca's form, Lewandowski said: "At Christmas, when we were at home, it was nice to think about what we did wrong and now until the end of the season we have many games. League, Cup, Champions League... we have to prepare well, it doesn't matter who we played against. In the second half we played with more patience, more experience."