During an interview with ESPN, Stan Wawrinka was asked how he had learned to defeat Roger Federer after all these years. Last year Wawrinka ended an 11-match losing streak to the Swiss Maestro in Monte-Carlo, and he struck again this year when he defeated Federer in straight-sets at Roland Garros en route to his second major title. Over the course of his career, Wawrinka owns a 3-16 record vs. Federer.

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In 2014, after he won the Australian Open, Wawrinka became the first Swiss man to rank ahead of Federer in the rankings in 13 years. It was the confidence from that huge victory that finally allowed the “Stanimal” to turn the corner against his rival.

“For sure it was always tough mentally to play him. But his game is, I would say, the worst in the big four for me, for my game to play. He’s mixing a lot, he’s playing really fast, serve and volley, he’s doing many, many things that I never really like. I would say since two years I’m playing much better, so that’s the key.”

Wawrinka said that his match against Federer in Paris this spring was one of the best of his career.

“The [match against Roger at the] French was one of my best matches ever,” he said. “I was playing really heavy and I finally found the confidence in myself to play my best tennis against him.”

“How did you get that confidence?” he was asked.

“Working out since many, many years, having the chance to start with Magnus Norman two years ago and little by little back to the top ten, first semifinal here two years ago, first Masters Cup in London, so, yeah, little by little.”

Wawrinka added: “Magnus found a few little things that gave me a little things that gave me a lot of confidence in my game.”

Wawrinka could end up facing his compatriot again in New York in the semifinals, but there’s a long way to go before that. Wawrinka will face Belgian Ruben Bemelmans in the third round on Saturday, while Federer will face Philipp Kohlschreiber.