MOSCOW – Defending champion Nikolay Davydenko defeated Florent Serra 6-1, 7-5 Tuesday in the first round of the Kremlin Cup.

In the women's draw, Svetlana Kuznetsova defeated Li Na 6-4, 7-5.

Sixth-ranked Davydenko had little trouble against the 53rd-ranked Serra in the opening set, but he needed a break in the 11th game to advance to the second round.

Davydenko is looking for his third straight title in Moscow.

The fifth-seeded Kuznetsova broke early in each set. She led 4-1 in the second set and had two match points serving at 5-3 before Li evened it at 5-5.

However, the Russian broke Li in the next game and served out the match on the fourth match point.

“I had a very tough first-round match,” Kuznetsova said. “Li Na beat many serious opponents this season and to win in two sets, I think, it's not a bad start to the tournament.”

Earlier, Michael Llodra was upset by Uzbekistan qualifier Denis Istomin 7-6 (2), 6-3, who was playing only his second ATP Tour match.

The 121st-ranked Istomin broke easily in the sixth game of the second set to stop the sixth-seeded Llodra.

Eighth-seeded Janko Tipsarevic of Serbia rallied to beat Russian qualifier Alexandre Kudryavtsev 4-6, 6-3, 7-6 (6).

Seventh-seeded Vera Zvonareva ousted Maria Kirilenko 6-4, 6-4, and Ekaterina Makarova beat Elena Vesnina 7-6 (4), 7-6 (1).

Sixth-seeded Venus Williams was scheduled to play Flavia Pennetta later Tuesday.

Kuznetsova, ranked No. 7, has lost all seven WTA finals this season.

The women's field includes seven of the top-10 players – including No. 1 Jelena Jankovic. U.S. Open champion Serena Williams, last year's runner-up, pulled out because of an ankle injury.