by defeating the 17th seeded Zheng Jie of China 7-5, 5-7, 6-3.
Venus Williams, the only active WTA Tour player to defeat Serena Williams at Miami, also moved into Wednesday's quarterfinals with a 4-6, 6-1, 6-4 clutch win over the tenth seeded Agnieszka Radwanska of Poland. Venus defeated Serena at Miami in 1999 and 2005.
The Williams sisters completed their third day of play in a row today as the wear and tear surfaced in each's tennis game. Serena lost her serve six times and committed 43 unforced errors.
“I was just happy to get through it,” Serena said, “because at one point I hit a ball into the bottom of the net and I thought, 'Wow, I haven't done this since I was a junior.' … I wasn't playing great.”
Venus, who hit 40 unforced errors to 43 winners, finished her match with an ace on matchpoint as did Serena. Venus hit 11 aces for the day.
“Every now and then, everybody has those kinds of matches. … I just had a lot of errors. Just errors, errors,” Venus said before adding “I feel good. I feel confident. I've been playing very well in the last few months.”
Venus has won four of her last five WTA Tour tournaments played and 23 of her last 24 matches.
And after winning second, third and fourth round Miami matches back to back, the Williams sisters have earned a day of rest before the quarterfinals competition. Wednesday Venus, a winner in Miami in 1998, 1999 and 2001, takes on the 26th seeded Iveta Benesova of the Czech Republic while Serena faces the unseeded Na Li of China.
While Serena would appear to be the overwhelming favorite in her quarterfinal match, Li is tied with Serena head to head 1-1 and defeated Serena in their last meeting in October of last year at the Stuttgart fourth round 0-6, 6-1, 6-4. Venus leads Benesova head to head 2-0, winning both matches in straight sets .
Should both Williams sisters win Wednesday, they would then face off for the second time this year in Thursday's women's semifinals. Venus leads Serena head to head 10-9 and won their last meeting in February at the Dubai semifinals 6-1, 2-6, 7-6(7-3).
And with this week's surprising opening round losses of the second seeded Dinara Safina of Russia, the third seeded Jelena Jankovic
of Serbia and the fourth seeded Elena Dementieva of Russia, the all-Williams semifinal seems all but inevitable with the winner
advancing to take the singles title in Saturday's final.
However in a surprising turn of events, should Serena Williams fail to reach the Miami
final, world number two Dinara Safina of Russia, will move into the top ranking Monday. Williams, who won the Miami title last year,
would lose too great a number of WTA Tour ranking points Monday should she not reach the final this year.