NEW YORK — He had to wait two extra days, but former University of Georgia star John Isner finally reached his first Grand Slam quarterfinal.

The 28th-seeded Isner won three tiebreakers Thursday at the U.S. Open and beat France’s Gilles Simon 7-6 (2), 3-6, 7-6 (2), 7-6 (4) in three hours, 39 minutes in a match delayed two days by rain. Isner will face fourth-ranked Andy Murray today.

Andy Roddick also won, beating fifth-seeded David Ferrer 6-3, 6-4, 3-6, 6-3. That means there will be two American men in the U.S. Open quarters for the first time since 2008.

Atlanta’s Donald Young wasn’t as fortunate, falling 6-2, 6-3, 6-3 to Murray in another match delayed two days by inclement weather. Young, who led 2-1 in the first set when play was suspended Wednesday, won only six games Thursday.

The champion is now scheduled to be crowned Monday (4 p.m.) instead of the usual Sunday slot for the fourth consecutive year. The women’s final also was moved, from Saturday night to 4 p.m. Sunday.

Joining Isner, Murray and Roddick on their side of the bracket was defending champion Rafael Nadal, who beat Gilles Muller of Luxembourg 7-6 (1), 6-1, 6-2.

Roddick finally finished his match, but he had to endure another obstacle: water seeping through a crack behind the baseline in Louis Armstrong Stadium, the tournament’s second-largest stadium. The match had to be moved from the 10,103-seat arena to 584-capacity Court 13.

“I thought the atmosphere was great. People packed in,” Roddick said.

Roddick next faces Nadal with a semifinal berth at stake.

“I’m going to have to play pretty aggressively now, similar to what I did today,” the 21st-seeded Roddick said. “He’s one of the greatest ever, so I’m going to have to have a repeat, at least.”

On the other half of the men’s draw, they already were into the quarterfinals, and No. 1 Novak Djokovic improved to 62-2 in 2011, advancing when his opponent, No. 20 Janko Tipsarevic, stopped playing while trailing 7-6 (2), 6-7 (3), 6-0, 3-0. Tipsarevic had his left thigh bandaged by a trainer at 5-0 in the third set.

Djokovic needed his own visit from the trainer for treatment on a bloody left big toe after sliding to get to a drop shot in the fourth set’s opening game.

In the semifinals, Djokovic will face 16-time Grand Slam champion Roger Federer or No. 11 Jo-Wilfried Tsonga, who were scheduled to play Thursday night.

In the women’s quarterfinals, 13-time major champion Serena Williams overcame shaky serving early to beat No. 17 Anastasia Pavlyuchenkova of Russia 7-5, 6-1 and improve to 17-0 on hardcourts this season. Seeded only 28th after missing nearly a full year because of health problems, Williams hasn’t dropped a set so far heading into a semifinal against top-seeded Caroline Wozniacki, a 6-1, 7-6 (5) winner against No. 10 Andrea Petkovic of Germany.

On the other half of the women’s draw, No. 9 Sam Stosur will play 92nd-ranked Angelique Kerber of Germany in the semifinals. Kerber upset No. 26 Flavia Pennetta 6-4, 4-6, 6-3, while Stosur easily defeated No. 2 Vera Zvonareva 6-3, 6-3. Zvonareva was the runner-up at the U.S. Open and Wimbledon last year.

Isner started slowly against Simon, managing just four aces in the first set, two of which came in the tiebreaker. He also struggled in the second set, losing his first three service games.

Isner finally found his groove in the third set with a pro-American crowd behind him. He launched 12 aces and put pressure on Simon by approaching the net.