NEW YORK (AP) – The U.S. Open went from the submerged to the ridiculous Thursday.

On a fourth straight day of rain and start-stop-start-stop action, organizers scrambling to finish the tournament on time were deprived of a show court because the Grandstand had absorbed too much water and couldn’t be dried enough for play.

Oh, and a women’s fourth-round match that began Monday finally finished, but not before being interrupted when the chair umpire was hit and hurt by a ballboy’s throw.

There was good news: The weather cleared up enough for 2001 champion Lleyton Hewitt, French Open winner Juan Carlos Ferrero, No. 5-seeded Guillermo Coria, and No. 13 David Nalbandian to reach the quarterfinals. Nalbandian knocked off Wimbledon champion Roger Federer 3-6, 7-6 (1), 6-4, 6-3.

Still, not your average big-time sporting event, huh?

“This was the weirdest situation that I’ve ever experienced in a Grand Slam tournament,” two-time major champion Mary Pierce said. “It was really, really weird to wait four days and play 20 minutes to finish the match.”

She lost 7-6 (2), 6-1 to No. 7 Anastasia Myskina, who later was scheduled to return to the court and face No. 2 Justine Henin-Hardenne in a quarterfinal.

Also asked to play more than once Thursday was No. 29 Francesca Schiavone, a 6-7 (5), 7-5, 6-2 winner over No. 15 Ai Sugiyama. Schiavone was supposed to play a quarterfinal against No. 6 Jennifer Capriati at night.

At least tennis was being played, though: A total of only four matches were completed from Monday through Wednesday. The tournament began Thursday with a backlog of 174 matches, which was alleviated somewhat by the cancellation of the junior doubles events. Junior singles matches were moved to an indoor tennis club 25 miles away.

Six men’s fourth-round matches either resumed or started Thursday afternoon, though not without touches of the bizarre.

Hewitt had his match, a 4-6, 6-2, 6-4, 6-2 victory over No. 11 Paradorn Srichaphan, switched from the Grandstand to Court 11, where a scoreboard wasn’t working. Hewitt next plays No. 3 Ferrero, who will make his debut in the U.S. Open quarterfinals after getting past the unseeded Todd Martin 6-2, 6-4, 3-6, 5-7, 6-3.

The water level underneath the Grandstand is so high that the surface feels soggy even when the water on top has been wiped away, grounds crew supervisor Joe Sexton said.

“We have to wait for the sun. If it sits in the sun for 12 hours, it could be playable again,” Sexton said.

Players were ushered out to all corners of the grounds in an effort to squeeze in matches, and Coria checked the map on the back of his credential to figure out exactly where Court 6 is.

Eventually, Coria found his way and finished off a 6-2, 6-3, 4-6, 6-2 victory over unseeded Jonas Bjorkman to set up a quarterfinal matchup with top-seeded Andre Agassi. Coria beat Agassi in the round of eight at the French Open.

Federer’s match against Nalbandian started at 3 p.m., and they played five games over 18 minutes until a sprinkling halted the proceedings. Next, they were sent back out 40 minutes later, warmed up and played all of one point before being shuttled to the locker room. Forty-five minutes later, the match resumed.

While an upset on paper – Federer was seeded No. 2 – Nalbandian now has won all five of their pro meetings. Federer was broken at love in the final game, which reached match point on a drop shot by Nalbandian that Federer didn’t even chase, and ended on a return winner. Federer had 62 unforced errors, 30 more than Nalbandian.

“It’s a disaster, this tournament,” Federer’s coach, Peter Lundgren, said before the match. “It’s too bad. It was so nice the first week. You just try to stay focused. It’s the same for everybody, but it’s tough.”

Schiavone-Sugiyama goes into the books with an official elapsed time of 2 hours, 36 minutes – but the match actually finished 66 1/2 hours after it began.

It started Monday night and was suspended at 6-6 in the first set, then resumed Tuesday, and Sugiyama served for the match at 5-3 in the second. She lost that game, and the match was halted. They were washed out entirely Wednesday, then were called out to play a little before 3 p.m. Thursday, four hours after they were scheduled to start.

Schiavone won three straight games to take the second set, but fell behind 2-0 in the third. That’s when play was stopped by the errant ball toss.

“I saw it coming out of the corner of my eye just before it hit me,” said chair umpire Lynn Welch, who oversaw the 2002 Open women’s final. “I was thinking: ‘That’s ironic. We just get back out here, and now there’ll be a delay because I’m hit.’ “

Welch was given a plastic bag filled with ice to put on cuts to her nose and temple, and she soldiered on.

Three minutes later, play was stopped because of rain.

When they came back out, Welch was wearing a Band-Aid, and Schiavone won six straight games to mercifully end the match. When Sugiyama floated a backhand wide on the final point, Schiavone raised her harms, dropped to her knees and covered her face, trembling.

“A crazy match,” Sugiyama said. “I understand with this weather it’s tough for everyone. But it is hard to keep a good balance. Having a match over four days: It happened here. I don’t think it’s going to happen again.”