Andy Murray ended an eight-match losing run against Novak Djokovic, beating the world number one for the first time in two years to win the Rogers Cup.
The British number one's 6-4 4-6 6-3 victory in three hours in Montreal earned him a fourth title of the year.
A first win over the Serb since the 2013 Wimbledon final will be a huge boost for Murray before the US Open in New York starts on 31 August.
The Scot dominated from the baseline as he claimed an 11th Masters title.
Murray is now set to overtake Roger Federer in Monday's new ATP rankings to return to number two for the first time since 2013.
The 28-year-old broke in the second game of the deciding set and held to establish a 3-0 lead before saving seven break points in a pivotal 18-minute fifth game to maintain his break advantage at 4-1.
Djokovic, chasing a 25th Masters title, saw off three championship points at 5-2 before Murray served out for the match.
He dedicated the victory to his coach Amelie Mauresmo, who gave birth to a baby boy on Sunday.
"I'm not sure she will have stayed up to watch this one but, Amelie, this one's for you," said Murray, who won his 35th career title.
In an absorbing, high-quality match, both players produced exquisite shots but it was Murray who dictated play, forcing a total of 19 break points on the Djokovic serve.
It was the first time Murray had beaten Djokovic over the full distance in a three-set Masters match, and it was his first win on a hard court over the Wimbledon champion since the US Open final in 2012.
"Things can better very quickly and they can get worse very quickly in sport," Murray told Sky Sports.
"It's important for me to analyse this week and work on areas to improve on before the US Open starts.
"I need to make sure I recover well from this and get ready and hopefully play a good tournament in Cincinnati. This match will be good physically and mentally for the build up for sure."