Even in the highly predictable age of the Big 4, tennis can still remind you, every once in a while, that anything is possible. But few things have seemed less possible, at the start of a week, than Jo-Wilfried Tsonga finishing it with wins over Novak Djokovic, Andy Murray, Grigor Dimitrov, and Roger Federer to take home a Masters title in Toronto. It had been a year since Tsonga had recorded a win over a Top 10 player, 18 months since he won a tournament, and six years since he had won a tournament at this level.

Tsonga played his best tennis in the final against Federer. From start to finish, he was dominant on serve. He made just 50 percent of his first serves, but he won 33 of 35 points when he did get them in, and he didn’t face a break point all match. Jo avoided a slow start, something that has plagued him against Federer in the past, and he played with intelligent aggression; he hit 26 winners, committed 18 errors, and was eight of 10 at the net. Most important, and perhaps surprising, Tsonga held his nerve when it looked likely that he would lose it.

In Monte Carlo in April, Jo had won the first set over Federer 6-2, only to give back the second in a tight tiebreaker and go away completely in the third. History appeared ready to repeat itself on Sunday when Federer saved four break points at 3-4 in the second set, and a championship point at 4-5. But Tsonga’s serve proved too strong again in the subsequent tiebreaker; he fired two aces and a service winner to close out a not-as-close-as-the-scores-indicated 7-5, 7-6 (3) win.

While he was only broken once, it was always a struggle for Federer today. He made 37 unforced errors against 26 winners, and was off balance on many of his strokes. He insisted on trying to come over his down-the-line backhand even when it was clear the shot wasn’t there for him; he missed two crucial backhands at the end of the first set, and didn’t hit a winner from that side all day. Federer also never found the timing on his bread-and-butter inside-out forehand.

He had said this week that he was happy that hard courts like Toronto’s have been playing faster recently, but if anything the court speed helped Tsonga from the baseline. Federer, struggling to deal with Jo’s depth and pace, caught the ball off of his back foot and buried shots in the bottom of the net. Despite making no inroads on Tsonga’s serve, he held on with some clutch serving of his own, as well as solid play at the net, where he was 27 of 33. Afterward, Federer, who had played all of his matches in the evening this week, said, “It was tougher conditions during the day.”

Still, having to play in sunlight can’t explain the disparity here; this was Jo’s day, and his tournament. Like Aga Radwanska and Venus Williams earlier in the afternoon in Montreal, Tsonga has inserted his name into the U.S. Open conversation, a place where he has been noticeably absent during the other majors this year. But let’s leave the Open speculation for the future. This was a day to enjoy one of the best sights in tennis, and one we’ve seen all too rarely of late: Jo-Willy’s winning grin.