French Open champion Rafael Nadal beat American Andre Agassi 6-3 4-6 6-2 to win the Montreal Masters Series.
The 19-year-old had lost only one of 53 service games prior to the final and eased to the first set.
He was finally broken by the veteran in the final game of the second set, but fought back in the decider, breaking Agassi twice to set up the win.
Victory gave the Spaniard his ninth title of the season and his first ever on hard courts.
It was also the Nadal's third Masters Series win, after victories on clay in Rome and Monte Carlo.
"I knew I could play good on hard courts, because I've had some good scores this year," he said.
"But for me winning here is very, very nice. I have confidence now.
"I said before I came here my goal is to win any tournament on hardcourt this year, and I have that in the first, no?"
Nadal had been keen to play the 35-year-old Agassi for the first time, and the American joked afterwards that he was glad to have played the youngster "before you retire".
He added: "We never even hit balls together, so you haven't even felt what his ball does, let alone what his best shots are.
"I think both players are a little out of sorts trying to figure that out."
Sunday's final had been interrupted by a rain shower with Nadal leading the match after clinching the first set.
The previous day, Agassi overcame Greg Rusedski 6-4 6-4 in their rain-delayed semi-final.
Meanwhile, world number two Nadal had beaten Frenchman Paul-Henri Mathieu 6-4 7-5 to reach the final.