It was almost as if someone played a cosmic joke at Wimbledon today. As soon as organizers took the plastic covers off the courts, the skies would darken. As soon as the players came out to hit a few balls, the rain would come. And almost as soon as play was halted, the skies would clear again, and the whole process would begin anew.

With four major delays, only two of the 96 scheduled matches were completed, but the fans who stuck around were rewarded when Steffi Graf pulled off a spectacular -- if sporadic -- 6-2, 3-6, 6-4 quarterfinal victory over Venus Williams. Williams certainly played with the kind of skill required to win here, approaching the net and reaching for every ball, but Graf was just slightly better when it counted, shaking off break point after break point to advance to the semifinals for the second time in as many Grand Slam tournaments.

"I have to say that for as many delays as we had, it was unbelievable tennis," Graf said. "Everybody that came into the locker room -- Pam Shriver, Virginia Wade -- was saying it was an incredible match, and it rarely happens that you have to play that kind of tennis in the quarterfinals."

Lindsay Davenport claimed the only other win of the day, defeating defending champion Jana Novotna, 6-3, 6-4, to advance to the semifinal on the opposite side of the draw. Since weather already wiped out a day and a half of play earlier in the week, organizers have moved the women's semifinals to Saturday and the final, originally scheduled for Saturday, to Sunday. The men, who have yet to complete a quarterfinal match, also have their final scheduled for Sunday, but if the rain whips up again their final could be moved to Monday.

"I was surprised we even finished tonight, because when we went out there [the final time] it was pretty dark," Graf said. "I think around 5-4 it started drizzling a little bit, but they kept us out there, and obviously I liked that, with the result."

Frustrated by the weather, fans spent most of the day camped at the food courts and hiding under covered portions of the stadium. Those who bravely remained in the stands huddled beneath umbrellas, occasionally performing the Wave and other maneuvers for BBC cameras.

"Would you believe that on BBC1 at seven minutes past five, you would get umbrella twirling and umbrella lifting?" one television commentator asked. "There could be a whole new series in this if they get a little cooking in."

It was not exactly the exciting fare English viewers had hoped to tune in to -- home favorite Tim Henman was due on court for his match against Cedric Pioline -- but the network had already exhausted its catalog of taped matches to show, sampling everything from the 1978 women's final to one of the over-45 men's doubles matches played Wednesday. Williams, who has been reading an instructional Italian book during breaks, even took the unusual step of watching a television replay of her own partially played match.

Only Davenport and Novotna were able to leave the grounds early. In winning her match, Davenport's speed proved as essential as her skill. The pair encountered only two rain delays before Davenport finished off Novotna by breaking her serve.

"I haven't had tremendous results here, so to get to the semis so far is huge, and to beat the best grass-court player probably is a big win for myself," Davenport said. "My grass-court game is getting better every year, and obviously I have a great opportunity in front of me now."

Davenport will next play one of two qualifiers, either American Alexandra Stevenson, 18, or Australian Jelena Dokic, 16. The pair's quarterfinal match was postponed today with Stevenson claiming the first set, 6-3, and Dokic close to claiming the second at 5-1. No. 8 seed Nathalie Tauziat of France was leading her match against Croatia's Mirjana Lucic, 6-4, 3-3, when rain ended all play.

The winner of Tauziat-Lucic will play Graf, although it is hard to imagine either player giving the 30-year-old German the kind of competition she faced today. Williams moved well all over the court, hitting with her trademark power and also displaying some finesse with intermittent volleying attempts.

She pushed Graf to the limit on Graf's service game several times, coming up with 15 break points, but in the end she converted only three of those break opportunities. (Graf had just six break chances but converted four of them.) Williams's most frustrating moment came after Graf broke her in the third set to go up, 3-2. Williams had the chance to even things immediately, piling up three break points in the next game, but she never converted and Graf held serve. Each player held serve for the remainder of the set, sealing the match in Graf's favor.

"I should have been more aggressive on the break points, and definitely she played well on the break points, because she knew she had to hold serve," Williams said. "I was definitely trying to be more aggressive and take the opportunities, but time ran out."

The win added to a marvelous summer for Graf, who celebrated her birthday last month by winning the French Open. "She's very tough," Graf said of Williams. "Obviously I knew that very well beforehand, and it's one of the reasons I'm happy right now. She is a strong player and with her serve, she moves incredibly well out there. She got to some balls I thought were over, and I mean, you could see what kind of potential she has. I'm extremely happy that I was able to go out there and play my game."

CAPTION: Steffi Graf rejoices after knocking off Venus Williams. Graf faced 15 break points and saved 12 of them.