Serena Williams might aspire to be the queen of women's tennis, but for now she's merely aiming to be a Toyota Princess.

On Friday, Williams clashed with another princess of tennis, Jelena Dokic, in the quarterfinals of the Toyota Princess Cup at Tokyo's Ariake Colosseum.

It was a battle royale that felt more like a final. Dokic played tough, solid tennis; Williams played even tougher. After all, she was wearing purple.

"I think the key is to get me in purple and it's hard to beat me," Williams said.

In only their second career meeting, the second-seeded Williams toppled her Australian opponent 6-3, 6-4 in 57 action-packed minutes. After the match, the American issued a warning to the rest of the players on the WTA Tour.

"I didn't play a very solid beginning of the year and I think if I did better at some of the little tournaments, my rating would be a little better," said the world No. 8, who beat Dokic in straight sets at the U.S. Open this year.

"It's inevitable that I'll be back. I was No. 4 once and it's inevitable that I'll be even higher than that soon."

Decked out in a purple tie-dye skirt and purple shoes -- "It's fuchsia," she later clarified -- Williams used a killer serve and a powerful baseline game to overcome Dokic. The match felt like a heavyweight title fight from the get-go. Both players engaged in long rallies that thrilled the 4,192 fans in the stands.

In the eighth game of the first set, the 33rd-ranked Dokic blinked first. Down 4-3, she simply couldn't handle Williams, who seemed to return everything in sight. Williams closed out the set in 28 minutes when Dokic plowed a service return into the net.

"She was serving really well," said the 17-year-old Dokic. "It was hard to do anything. I don't think I moved as well as I wanted to."

The second set began with each player losing serve twice. The eighth-seeded Dokic gained some momentum when Williams' serve momentarily went south. She claimed eight straight points, good for a 3-2 lead.

That's when Williams shifted into high gear and seized control of the match. She found her serve when it counted most and went on to win four of the final five games, closing out the match with her eighth ace.

"I was actually proud of myself," the 18-year-old Williams said. "During the match I was thinking, 'Wow Serena, out of a 10 today I'm going to give you an eight.' But then in the second set I began to lose my serve, which is one thing I've been working on this whole year."

In the semifinals, Williams will face Daja Bedanova of the Czech Republic, a 5-7, 7-6 (7-0), 6-2 victor over American Amy Frazier. What does Williams know about Bedanova? Absolutely nothing. That's where sister Venus enters the picture.

"Whenever I need to play someone I call Venus, and Venus has played her. So I'm going to call Venus tonight. . . . She's at home, she's actually in school right now. When I get back I have to go to school."

Another American, top-seeded Monica Seles, also advanced to the semis on an overcast afternoon. The bronze medalist at this year's Sydney Olympics downed Japanese wild-card Shinobu Asagoe 6-3, 6-4 in a contest that was closer than the score reveals.

"The match started off strangely with four breaks and it was close all the way," said Seles, last year's runnerup and a two-time Princess champ. "I definitely knew her serve is her weapon and she hit some nice forehands down the line today."

Asagoe, who had advanced further than ever before in a tournament at home, looked brilliant at times. However, the occasional unforced error by the Japanese enabled Seles to gain the upper hand. Despite the loss, Asagoe found a silver lining.

"It was my first match against a foreign opponent (in this tournament) and up until now I've been playing Japan players, and all I hear is 'Go Yuka!' or 'Go Ai!' " said Asagoe. "But today, I got to hear my own name. Some in the press were even cheering me on. I think I found some allies in the press."

In the semis, Seles will face Frenchwoman Julie Halard-Decugis, who beat America's Kristina Brandi 1-6, 6-1, 6-4. A good portion of the crowd backed Halard-Decugis, who teamed with Ai Sugiyama to win the doubles title at the 2000 U.S. Open.

"I'm looking forward to playing Julie in my next match, but that's as far as I'm going to look," said Seles, who hasn't dropped a match to anyone outside the top four this year. "But Serena, I don't have a good record against her."

There's another thing Seles will have to worry about if she faces Williams in the final. Serena will be wearing purple.