The Spaniard said he played with an intensity missing in 2011, an encouraging sign with a year of intense competition ahead.
"(I'm) very happy with my level during both weeks. I realize the whole tournament I did well. I did a lot of very positive things, much more than in 2011 for most of the time," he said.
"I played more aggressive. I played more winners than ever. My serve worked well. The mentality and the passion were there.
"So that's very positive aspects on the whole game. So I just lost the final of a grand slam. I am not happy to lose the final, yes, but that's one of the losses that I am happy with in my career."
Djokovic took Sunday night's epic final -- the longest in Grand Slam history -- 5-7, 6-4, 6-2, 6-7 (5/7), 7-5 in a match spanning nearly six hours.