NEW YORK, Sept 5 (Reuters) - Felix Auger-Aliassime broke through Frances Tiafoe"s defences to win 4-6 6-2 7-6(6) 6-4 at the U.S. Open on Sunday in a fourth-round battle between two of the sport"s brightest young talents. Both players came into the tie at Arthur Ashe Stadium on the back of tough five-setters and it was 23-year-old Tiafoe who started the brighter, going up a break after the first game and shutting down all eight of the Canadian"s break point opportunities to go up 1-0. Auger-Aliassime, 21, came roaring back in the second set, however, winning all but one of his first-serve points and making just four unforced errors to level the match. Auger-Aliassime, seeded 12th, rocketed four aces in the ninth game of the third set and twice had a chance to close out the set in the 10th but American Tiafoe dug in his heels to hold serve and fire up his fans in the New York crowd. Feeding off the energy, Tiafoe then went 3-1 up in a tiebreak but Auger-Aliassime battled back before clinching the final three points to close out the set. Auger-Aliassime broke to kick off the fourth set and immediately fought off three break points to hold his own serve, going on to clinch the match with a forehand winner and reach his second consecutive Grand Slam quarter-final. Tiafoe left the court to wild applause and his opponent praised his efforts. "I understand supporting your fellow American -- he deserves the applause, he’s done an amazing effort," he said in an on-court interview. Tiafoe said there had not been much between them. "It was a tough start for me – a lot of nerves," he said. "I played a great second set and then the third set was almost a coin toss." Next up for Auger-Aliassime is 18-year-old Carlos Alcaraz, the youngest male player to reach the quarter-finals at Flushing Meadows in the Open era. read more "He’s a great player. At some point, age is just a number and he already feels like a player that’s established," said the Canadian.