Andy Murray hailed his straight-sets win over world number one Roger Federer as the greatest of his career.
Murray ended Federer's 55-game unbeaten run on hard-courts
The Briton became only the second man this year to beat Federer as he won 7-5 6-4 at the Cincinnati Masters.
Murray, who plays Robby Ginepri in the third round, said: "Even if he wasn't playing well, him at 70% is better than 95% of the world's players.
"He's played bad matches before and come through all the time, so it was still the best win in my career."
BEFORE THIS FEDERER HAD...
Won 55 straight matches in North America
Only been beaten by one player (Rafael Nadal) this year
Not lost in straight sets for 194 matches (when Gustavo Kuerten beat him in May 2004)
Reached 17 successive finals (one short of Ivan Lendl's record)
Murray's new coach Brad Gilbert said afterwards: "The best four words in tennis are: game, set, match, Murray - and that's what we heard.
"It was a great win for the kid and, hopefully, that will just boost his confidence even more that he can play with anyone in the world.
"The most important thing when you are 19 is to keep getting better."
Murray, who beat Tim Henman on Tuesday, broke Federer's serve seven times as he ended the Swiss star's run of 55 straight hard-court wins.
He said: "I made him feel uncomfortable. I just felt it was my time to win against him.
I don't think physically I'm good enough to win a Grand Slam just yet
"I didn't get nervous at all, and just kind of went with it. That's what happens when it's meant to be.
"I think now I'll have a bit more belief going into Grand Slams that I can go deep, although I don't think physically I'm good enough to win a Grand Slam just yet.
"It may take a few years. But my game is getting there, it's getting better all the time and Brad has helped a lot.
"Physically, I'll get stronger. I think I'll have a good chance in a couple of years.
"To win a Grand Slam you have to be in unbelievable shape. I just think I need to get better physically.
"If I was to win every match in straight sets then, yes, I probably could do it. But if I have a lot of long matches, then I'm probably not strong enough to do it just yet."