Key Biscayne, Fla. ? Maria Sharapova and Venus Williams reached a crescendo in the final game, swapping shrieks that accompanied their shots in a series of furious exchanges.

Sharapova was a little louder, and a bit better.

Holding her ground and her serve when Williams mounted a comeback, Sharapova erased six break points to close out a 6-4, 6-3 victory Thursday in the semifinals of the Nasdaq-100 Open.

The No. 2-seeded Sharapova advanced to her first Key Biscayne final. On Saturday, she’ll meet the winner of the match Thursday night between unseeded Kim Clijsters and No. 1 Amelie Mauresmo.

Williams, seeded eighth, ended a streak of six consecutive losses to her sister by beating Serena in the quarterfinals. But with Serena watching from the stands, Sharapova refused to let Venus pull off another upset.

Hitting with the precision of a ball machine, only noisier, Sharapova consistently placed her powerful serves and groundstrokes within inches of the lines. The reigning Wimbledon champion punctuated each big swing with her familiar high-pitched grunt and committed just 12 unforced errors in 115 points.

“I thought I played really well,” Sharapova said. “I was in control for most of the match.”

By the end, the grinding rallies had Williams shrieking too. The final game lasted 16 points, with both players racing corner to corner in pursuit of shots. Williams failed to convert her only break-point chances in the match and finally sailed a weary backhand long on match point.

“She’s got a lot of fighting spirit out there,” Sharapova said. “I was very proud of myself for being able to win that game. It was a very tough one.”

Williams offered a less gracious assessment. She blamed fatigue for her defeat and only grudgingly gave credit to Sharapova.

“She played fairly consistently,” Williams said. “I probably shouldn’t have made so many mistakes. I’ll remember not to next time.”

In men’s play, top-ranked Roger Federer advanced to the semifinals by beating No. 6-seeded Tim Henman 6-4, 6-2. Federer, bidding for his first Key Biscayne title, extended his winning streak to 20 matches and improved to 46-1 since the start of last year’s U.S. Open.