Until this year, Stanislas Wawrinka had won four titles in his career, all of them at the ATP 250 level. His raw talent was always there, along with a gorgeous backhand, but his mentality was not right for winning Grand Slams or bigger tournaments.

That all changed in Melbourne this year, when he had a major breakthrough while finally defeating Novak Djokovic in an epic quarterfinal. There has been a noticeable difference in his attitude this year when facing adversity and against previously-unbeatable opponents. Since then, he has beaten both Rafael Nadal and Roger Federer, in the Australian Open and Monte Carlo finals, respectively.

Stan has branded himself as a vocal, primal player. Nicknamed the “Stanimal,” he lets his emotions fly on court. You know when he’s happy, and you know when he’s angry. He doesn’t hold back, whether after a good point or a bad one. He will unleash the same roar whether he just won a set or hit an awful error, but you always know what his shouts mean.

Today, though, we saw a different Stan. Wawrinka came out his usual self, although he was a little toned down as always against Federer, perhaps out of respect for his friend and compatriot. Stan was strong in the first and second sets, but he began asking for a doctor halfway through the second set.

Throughout the third and fourth sets, it was clear that something was ailing Wawrinka. His serve lost a significant amount of speed, and his groundstrokes were nowhere near as crisp. He lost the third set and fell behind a break early in the fourth set. Whether it was just fatigue or some illness we don’t know, but it was clear that he was not at his best.

For the rest of that fourth set, we saw a different Stan. Wawrinka didn’t expend energy celebrating his big opportunities. He did not roar in the big moments. Wawrinka just played point after point, some of them exceptionally well. He forced Federer to fight for every point, almost breaking back when his countryman served for the match.

Seeing this “Silent Stan” inspired some thought. It is clear that he was holding back to conserve energy for the points. It was also clear that this worked for him. He got a second wind and played strong tennis for the remainder of the match. He went toe-to-toe with Federer on grass, something few players in the world can do.

Stan plays as the “Stanimal” because it works for him. It lets him unleash mentally and during play. And it might also get in the mind of some opponents. Then again, there are other opponents that it can fire up. Either way, we saw today that Stan can play top-notch tennis without it. That doesn’t mean that he has to give it up, and it doesn’t mean that he should. It just means that, if Wawrinka ever needs to be “Silent Stan” again, he knows he can do so and still be in Slam-contending form.