Serena Williams, boosted by a short rain delay, rallied for a 6-4, 7-6 (7-3) win over world No. 1 Martina Hingis of Switzerland in an emotionally charged semifinal today at the $4.775 million Lipton Championships. Now Venus Williams must beat the most decorated player in women's tennis, Germany's Steffi Graf, tonight to secure the historic final matchup.

Serena Williams has won 16 straight matches and is in search of her third title in 1999, trying to do it in succession. She captured the Open Gaz de France and followed it with a triumph in the Evert Cup.

Williams, 17, lost her first two matches to Hingis, who will remain No. 1 in next week's WTA rankings, and appeared headed for a third loss in as many all-time meetings. The start of the match was pushed back by the rain and Hingis rattled off wins in the first four games -- including 12 straight points, before a brief sprinkle gave Williams a 10-minute respite.

Hingis, 18, won the first point after the break, but the 16th-seeded Williams exploded and won the next eight games as the match took an astounding turn.

Williams said she lost her composure on the point that started Hingis' run of 13 straight points.

"That was really something. I couldn't get it back together after that," Williams said. "I even lost the first point after the rain. ... That's the way I seem to play. I win all these games in a row. Even the other day against Amanda (Coetzer), I won a set 6-0."

But Williams lost control nearly as quick as she gained it as Hingis roared back to win five consecutive games to grab a 5-2 lead in the second set. But Williams fought back to get to 5-5 and each held serve to force the tiebreaker.

"She was leading 2-0 quite quick," Hingis said. "After that, I didn't have many chances. She was always a step faster than me. I was all of a suddend standing there, didn't know what to do. Then I had this big chance, going up 5-2, serving, all this. I let it go."

Hingis appeared to have won the second set, but a ball was controversially called out in favor of Williams. Hingis then argued, to no avail, with the chair umpire.

"I'm playing here in the U.S. against an American," Hingis said. "It can happen. You don't lose the match because of one point. It's set point, so you definitely don't love it. That call, it happens. You know it. Of course, you're frustrated at that stage. but I had another chance to make the game, just win the set again."

The powerful Williams lost the first point of the tiebreaker but rallied with three straight winners and never trailed again. Williams hit a shot wide right and was long on a return, allowing Hingis to even the tiebreaker, but won the last four points to grab the match.

"It really was a great effort for me," admitted Williams, who is bothered by a cold. "My knee is not feeling the best. I don't think mine (cold) is as bad as Venus'."

For Venus Williams, 18, to maintain a chance at defending her title, she must knock off five-time champion Graf in a battle between the respective sixth and seventh seeds.

The older sister earned her most prestigious title here last year and defended her first professional title at Oklahoma City three weeks ago, the same day Serena won her first singles title in Paris.

Graf has won 21 straight matches at the Lipton since the 1993 final and is 60-5 lifetime at this event, reaching the semifinals in all 11 appearances. Last week, the former No. 1 player lost to the younger Williams in the final at Indian Wells, California.

Graf, 29, leads 2-1 in the all-time series, but Williams was a 6-3, 3-6, 6-3 winner in the last meeting, earlier this year in the semifinals at Hannover on carpet. To beat Williams, Graf will call on her experience -- she has 106 career WTA TOUR singles titles, has spent a record 377 weeks at No. 1 and is the only player (male or female) in tennis history to have won each Grand Slam singles title at least four times.

On the men's side, seventh seed Richard Krajicek of the Netherlands advanced to his second ATP Tour final of the year by overpowering No. 14 Thomas Enqvist of Sweden, 6-4, 6-2, on Thursday.

Krajicek will face former world junior champion Sebastien Grosjean of France in the final on Saturday. Grosjean, who advanced to his first ATP final, dropped his first set against Francisco Clavet of Spain before rallying for a 3-6, 6-3, 6-1 victory.

Krajicek, the 1996 Wimbledon champion, has won 12 of his last 13 matches and will seek his second ATP Tour title of the year and second career Super 9 title. He won the Guardian Direct Cup in London last month for his 16th career singles title.

With a victory Saturday, Krajicek will move from No. 7 to a career-high No. 4 in next week's ATP rankings.

The 20-year-old Grosjean has enjoyed a breakout week, advancing to his first Super 9 semifinal, upsetting 16th seed Gustavo Kuerten of Brazil in the second round and ending Carlos Moya's run as the No. 1 player with a fourth-round win over the Spaniard on Monday.

"It's like a dream," Grosjean said. "I am playing my best tennis, and (beating) some very great players. I am going to my first final on the tour and its a Super 9. It's wonderful for me, it's a dream."

The men's champion receives $360,000 and the women's winner pockets $265,000. The women's championship is Sunday.