In-form Jo-Wilfred Tsonga beat Roger Federer 7-5 7-6 (7/3) to claim his latest big-name scalp and lift the Rogers Cup in Toronto.
The Frenchman had already knocked out world No 1 Novak Djokovic, two-time champion Andy Murray and seventh-seeded Grigor Dimitrov to reach his first ATP Masters 1000 final since losing to Federer in Paris in 2011.
And he made the most of his opportunity in Toronto, breaking the second seed to take the first set and then holding his serve in the tie-break to secure the victory
However, he had earlier spurned a championship point on the Federer serve at 5-4 and advantage, but put his shot into the net.
The Swiss ace finally held his serve after five deuces to level at 5-5 and the match went with serve to the tie-break.
World No 15 Tsonga, who was bidding for his 11th career trophy, secured the crucial break to go 4-3 up and won both his serves to hold three championship points.
Federer went into the net to hand the French player the victory and his fourth straight win over a higher-seeded opponent, as well as dash his own hopes of a landmark 80th career title.
It was Tsonga's second career Masters 1000 title, coming almost six years after his first at Paris Bercy in 2008.
His serve played a major part in his victory, with the 29-year-old hitting 11 aces and winning 94 per cent of his first serve points and 63 per cent of his second serve points.
But Federer contributed to his own downfall, making 37 unforced errors to Tsonga's 18.
A jubilant Tsonga said: "It is always a pleasure for me to be here. Two years ago I had a big problem here with my knee but now it's the past and today I have the trophy and I'm just so happy!"
Federer was gracious in defeat, saying: "I had a great time, even though the match didn't go as I was hoping it to go but Jo deserves this title, he beat unbelievable players along the way and backed it up with another great final, so congrats, I'm really happy for you."