Three-time Grand Slam champion Wawrinka had two knee surgeries in 2017 and struggled to rediscover his best form initially but he has returned to 28th in the rankings.
In Paris this year he has looked close to his best with wins against dangerous Chilean Cristian Garin, Grigor Dimitrov and Greek sixth seed Stefanos Tsitsipas in a five-hour last-16 classic -- the longest singles match of his career.
He pushed Federer all the way on Tuesday before losing 7-6(4) 4-6 7-6(5) 6-4, ending his hope of a first Grand Slam semi-final since he lost to Rafael Nadal in the 2017 Paris final.
But he could see the bigger picture.
"I think in general the tournament was great for me," Wawrinka told reporters. "I won some big matches, especially against Garin, playing super well against Dimitrov.
"Tough match in two days followed by Tsitsipas, big battle, five hours. I was super happy also to be ready physically after all that time on the court.
"Today to give another big battle against Roger was a tough one for sure. But it was a great battle. This is really good for the future. It shows me I have done the right things."
Wawrinka said it was a completely different feeling to last year when he lost in the opening round and his ranking slipped into the 200s and many thought his best days were gone.
"I'm more positive than sad or disappointed with the result," the 2015 French Open champion said.
"I know how I left here last year when down in the rankings, like 260 or something. I'm going to be back in the top 20. For
me, I'm happy with that."
Wawrinka's three career wins over Federer all came on clay, including a quarter-final triumph in 2015 when he went on to deny Novak Djokovic his career Grand Slam in the final.
He said Tuesday's loss came down to tiny details.
"Today I was playing great and he was playing the way I expect him to play against me," he said.
"It was just about who's gonna play the best in those
important points, and he did that better than me today."
(Reporting by Martyn Herman, editing by Pritha Sarkar)
