(Agencies)
Updated: 2008-04-02 09:00

KEY BISCAYNE, Florida - Defending champion Serena Williams beat Kaia Kanepi 6-3, 6-3 at the Sony Ericsson Open on Monday and will renew one of tennis' best rivalries with Justine Henin in the quarterfinals.

Serena Williams returns a shot from Kaia Kanepi of Estonia during a fourth-round match at the Sony Ericsson Open tennis tournament in Key Biscayne, Fla. Monday, March 31, 2008. [Agencies]

It's a rematch of last year's final, which Henin lost after Williams erased two championship points.

"Actually it's a very good memory from last year, even if I had match points and I lost the match," Henin said. "It was a day that I understood that I could win against Serena, and that I could do it in Grand Slams three times in the same year."

Williams has lost their past three meetings, all last year, at the French Open, Wimbledon and the US Open. But she's sure to be fired up again for Tuesday's match.

"We definitely bring out some of the best tennis in each other," Williams said. "And she tends to play really well against me - probably better against me than other opponents. So it's definitely a good match for me."

On Monday, top-seeded Henin defeated Elena Vesnina of Russia 6-2, 6-2 and advanced from the fourth round with No 3 Svetlana Kuznetsova and No 4 Jelena Jankovic, both of whom overcame match points in earlier rounds.

No 6 Venus Williams joined her sister in the quarterfinals by beating 17-year-old Caroline Wozniacki 6-3, 6-3. No 1 Roger Federer reached the fourth round on the men's side.

The No eighth-seeded Serena Williams looked sloppy in a third-round victory, when she committed 60 unforced errors, but she pared that total to 24 against Estonia's Kanepi. It was clear Williams meant business: She screamed "C'mon!" when she hit an ace, then shrieked when she hit a sloppy shot, and both times she could be heard in the top row of the stadium.

"I definitely feel like I was focused," Williams said. "I felt like I had to be. The other match was definitely a good eye-opener."

Henin hit eight aces and held every service game against Vesnina. Kuznetsova defeated Shahar Peer of Israel 7-6 (4), 6-3 and Jankovic swept Zheng Jie 6-4, 7-5.

A superior serve and return helped Venus Williams defeat Wozniacki, a Dane who has won 14 matches this year to climb to a career-best 43rd in the rankings. Williams lost only six points on her first serve and repeatedly slammed Wozniacki's serve for winners.

Williams is a three-time Key Biscayne champion, but her most recent title in the event came in 2001.

"I definitely feel like I'm playing well," she said. "I'm always trying to take it to another level, regardless. If I'm playing on cloud nine, I'm trying to get to cloud 10, and actually cloud 11."

In the quarterfinals, Venus Williams will play Kuznetsova, and Jankovic will meet Elena Dementieva, a 6-3, 6-2 winner over Germany's Sabine Lasicki.

Lindsay Davenport hit a bump in her career comeback when she lost to Dinara Safina 6-3, 6-4.

It was a flat followup to Davenport's win Sunday over No 2-ranked Ana Ivanovic. That upset victory was the biggest for Davenport since she returned to the women's tour last summer after becoming a parent.

"That's the thing with tennis," Davenport said. "Every day you start over. But hopefully more positives than negatives come from this tournament."

Against Safina, Davenport totaled 34 unforced errors, including six double faults. She hit only 20 winners to 31 for Safina, seeded 13th.

"She did everything better than I did," Davenport said. "I came up against a player today that was real intense and real eager to win."

Safina will face fellow Russian Vera Zvonareva, who defeated Ai Sugiyama 6-2, 6-7 (5), 6-0.

Federer, still seeking his first tournament title this year, advanced to the fourth round when Robin Soderling retired because of illness trailing 6-4, 3-0. Soderling lost the last five games and the final 10 points.

"You're sort of happy you got through to the next round," Federer said. "You're not happy for your opponent, because it's never a way you want to win a match, but you've got to push him to give up."

No 4 Nikolay Davydenko beat Simone Bolelli of Italy 6-7 (5), 7-5, 6-1, and newly engaged No 6 Andy Roddick converted only two of nine break-point chances but still beat Czech qualifier Ivo Minar 7-6 (4), 6-4.

Afterward he confirmed he became engaged to swimsuit model Brooklyn Decker in early March.

"I think I lost half my fan base today," he said.

Julien Benneteau ousted Australian Open finalist Jo-Wilfried Tsonga 6-3, 6-3 in an all-French encounter, and Janko Tipsarevic of Serbia reached the fourth round of a Masters event for the first time, at the expense of Thomas Johansson of Sweden 6-4, 6-4.