NEWPORT, R.I. — Meg Mallon didn't have the luxury of making sure the fog cleared before warming up for the U.S. Women's Open.

Scheduled to tee off in the third group at the Newport Country Club on Thursday morning, Mallon headed to the range five times after officials announced a series of half-hour postponements. Five times — and don't think she wasn't counting — she went back to the clubhouse to wait out another delay.

"I could never relax. I had to be ready to play," the two-time Open winner said after fog forced the tournament to push back its start until Friday. "Controlling your adrenaline throughout is the hardest thing. By the time I would have played, I was all out of energy.

"I haven't done anything, and I'm exhausted."

Although the threatened rain didn't come during the day Thursday, fog enveloped the seaside course the entire morning. The first groups, originally scheduled for 7 a.m., were put off for 30 minutes, and then another 30 minutes, and so on until play was finally called at about 2:45 p.m.

It was the first time since the 2003 Masters that the start of a major was postponed one day.

The par-71, 6,564-yard course — the longest for a U.S. Women's Open at sea level — has no artificial irrigation system. Storms dumped 13 inches of rain on the grounds during the last six weeks, and 3Z\x inches last weekend alone.

But rain, which had been forecast, wasn't the problem. "In that sense, we're probably going to have a better golf course from here on out than we anticipated having," said Mike Davis, the USGA rules director.

Davis said that fog was harder to deal with than rain, because it was unpredictable. For much of the morning, there was less than 75 yards of visibility at some spots.

"In other words, you're 75 yards from the green and you can't see the flagstick," he said. "If the player can see where she is trying to hit the ball, that's what we consider. And that's what held us back today."

For a brief window after 2 p.m., visibility improved to 300-400 yards.

"That's really quickly where we got excited thinking we're actually going to get in some golf today," Davis said. "And, literally, 5-10 minutes later it rolled back in and we were done."

Play was rescheduled for Friday morning — with Mallon back in her 7:22 a.m. tee time. The plan is to play 18 then, and another 18 on Saturday before finishing with 36 holes Sunday.

It's the first professional major at Newport, one of the five founding clubs of the USGA, since it held the U.S. Amateur and the U.S. Open one day apart in 1895. Tiger Woods won the second of his three straight U.S. Amateur titles here 100 years later.

"If Mother Nature doesn't cooperate, we may be into Monday," Davis said. "And obviously if there's an 18-hole playoff, we're there already."

Mallon, 43, is one of the few players in the Newport field to remember the last time the Open went had a 36-hole finish. She was in the final group at the Atlanta Athletic Club in 1990 when Patty Sheehan gave up an 11-stroke lead Sunday to lose to Betsy King by one stroke.

"You could just see the adrenaline and energy leaving her body as the day went on," Mallon said. "It makes it tough. It's hard enough playing 18 holes on an Open setup. It's a long, hard day. It's exhausting. You have to have all of your energy, for sure.

And that experience might help her this Sunday.

"Absolutely. I learned an awful lot from that day," she said. "But I don't want to share that with anybody else, so please don't put that down."