By Will Swanton
NEW YORK (Reuters) - Whisper it quietly but a beast might be stirring at Flushing Meadows.
Milos Raonic is the sleeper of the U.S. Open. Touted as a leading member of Generation Next in men's tennis, the powerful 22-year-old Canadian roared into the fourth round on Saturday with a 6-7(4) 6-4 6-3 6-4 win over Spain's Feliciano Lopez.
Raonic's thunderous serve has landed him a chart-topping 65 aces for the tournament. His heaviest delivery of 145 miles per hour is the quickest of the event.
His relatively seamless progression through the draw comes on the back of his recent appearance in the final of the Montreal Masters against Rafa Nadal and a move up to number 11 in the world rankings.
While the American tennis fraternity sweats on the arrival of a men's player to match the deeds of retired superstars Pete Sampras and Andre Agassi, the relaxed and quietly-spoken Raonic admitted he benefitted from lower expectations in Canada.
"There's a lot more pressure on the Americans," he said.
"One advantage they have growing up is that maybe there are more wildcard opportunities as an American.
"I'm doing a lot of stuff in uncharted territories, so people are very supportive of it. Whereas I feel it's a little bit unfair to the American players, everybody expecting another Pete and Agassi to be there on the top.
"Everybody is always asking, why isn't their playing doing this? This is an American. I think that's the big difference."
Ranoic, though, denied he was flying completely under the radar compared to his U.S. counterparts.
"I think the attention is the same," he said. "I don't know how to say it, but one is more negative than the other because they (Americans) are expecting a lot more. In Canada, it's a lot more positive to be in the situation I am right now."
Lopez was unable to break the serve of his 1.96 m tall opponent in their two hours and 37 minutes on Court 17.
"I was really struggling with getting anywhere on his service games, but I found my own a little bit," Raonic said.
"I was getting confidence and calming down. I wasn't feeling as nervous about the whole situation. I was a little sloppy at the net at times, but I started cleaning things up from the baseline."
Montenegro-born, Toronto-raised and now resident in Monaco, Raonic's biggest concern appeared to be his sunburned face.
"I didn't have any (sun tan lotion) on, so I will probably pay for that tonight," he said.
Raonic has yet to reach the quarter-finals at a major.
His next assignment will be against eight-seeded Frenchman Richard Gasquet, who reached the fourth round when 32nd-seeded Russian Dmitry Tursunov retired.
The winner of the Raonic-Gasquet clash will have a winnable quarter-final against Spain's David Ferrer or Serbian Janko Tipsarevic.
In his only previous meeting against Gasquet, on hard courts at Cincinnati last year, Raonic won in straight sets.
"I'm going to have to focus a lot on myself and not let him get into a rhythm," he said.
"I thought I did that pretty well today. Always when I had a short ball, I would go for it, even on the backhand side. I have to let them never get into a rhythm."
(Editing by Gene Cherry and Nick Mulvenney)