NEW YORK -- Canada's Milos Raonic has claimed his spot in the fourth round of the U.S. Open.

The fifth seed from Thornhill, Ont., held off unheralded Victor Estrella Burgos of the Dominican Republic for a 7-6 (5), 7-6 (5), 7-6 (3) victory on Saturday.

Raonic hammered over 22 aces and 52 winners, breaking on three of 11 chances against the 34-year-old -- the oldest man left in the draw -- in the match that took two hours and 45 minutes.

"I've been very fortunate this year to play well in tiebreakers," said Raonic. "I'm playing well when it counts the most. I was able to continue that today. My goal is to keep getting better, thankfully that's been the trend."

The 23-year-old Raonic will next face tenth-seeded Kei Nishikori of Japan, who defeated Argentine Leonardo Mayer 6-4, 6-2, 6-3.

The Canadian won the last meeting between the two, in the fourth round at Wimbledon, but lost to the Japanese player in Madrid last spring and Tokyo last fall in the Japan Open final.

Raonic, who reached the Wimbledon semifinals, had to battle both his opponent and a crowd of local Dominicans who gave their player loud and sustained support in the biggest match of his career.

"Victor played really well, this is a very special week for him," said Raonic. "As for me, I've got to keep battling, getting through on grit and trying to find a way to win."

Raonic needed to work to win each of the opening two sets against his No. 80 opponent, who finally qualified to play in New York after missing out on five previous occasions.

Seventh-seeded Eugenie Bouchard hopes to join Raonic in the round of 16. The 20-year-old from Westmount, Que., was set to face Czech veteran Barbora Zahlavova Strycova, the 30th seed whom Bouchard has defeated in previous meetings in Osaka last autumn and in Nurnberg on clay this spring.