Cole Palmer struck for Chelsea, though they were comfortably beaten as Harry Kane scored twice, once from the penalty spot, and Trevoh Chalobah put through his own net as Bayern won 3-1.
"I think the first 20 minutes we started very good, creating two or three clear chances without conceding anything," said Maresca after the final whistle in Munich.
"Then we conceded the goal, and we can avoid that kind of goal, and the dynamic changed a little bit. But even with that we continued to play, we scored a goal.
"We started the second half much better than the first half, until the goal we conceded. Then again for 10 minutes after the goal we conceded we were not good enough, but at the end we tried again, we scored the second goal, but it didn’t count.
"In this competition against this team requires you to be fully focused to play like that for 95 minutes. I think we played good but not for the entire game."
On the performance, Maresca also stated: "Personally, I am happy with the performance, because we know how difficult it was to come here against this team. We knew that it would be a very tough game.
"Again, in the first 20 minutes we didn’t concede anything, we created two or three clear chances. Then we conceded a goal and it changed the game.
"Even with that we were in the game until the end. It’s very difficult to come here and control the game for 95 minutes, that is not realistic. Overall I think we competed very well."