NEW YORK — If any player needed a break at the U.S. Open, it was Rafael Nadal.

His stomach muscles clearly hurting, the third-seeded Nadal got some time to heal when his match against No. 11 Fernando Gonzalez was postponed because of rain late Thursday night.

Nadal won the first set and was leading 3-2 in the second-set tiebreaker when the second rain delay of the night hit.

Tournament officials waited about 90 minutes before calling play — the first postponement after 10 straight days of fantastic weather at Flushing Meadows.

The postponement, combined with a forecast calling for a 90 percent chance of rain today, threatened to place the U.S. Open schedule into flux and made it almost certain that the winner of Nadal-Gonzalez would have to pay for the break he got Thursday, with a packed schedule through the weekend.

Nadal, the six-time major winner trying to complete a career Grand Slam, has been reluctant to talk about the injury. He doesn't want to let his opponents know his weaknesses. But the medical timeout he took early in the second set, with the trainer poking and massaging his stomach, told the story.

The delay meant the biggest — and only — winner from Thursday's singles was Juan Martin del Potro. The sixth-seeded Argentine made his second Grand Slam semifinal by beating No. 16 Marin Cilic 4-6, 6-3, 6-2, 6-1 earlier in the day, when the wind was blowing hard in front of the rainstorm that came later.