Serbia’s Ana Ivanovic booked her place in the second round of the Olympic women’s singles Saturday, knocking out Christina McHale of the United States.

Former French Open champion Ivanovic prevailed 6-4, 6-5 on the Wimbledon grass on the first day of the Olympic tennis tournament.

"It was a little bit up and down, we both started off a little bit nervous but that's normal for the first match. I'm really happy that I managed to stay calm and winning, too,” Ivanovic said.

McHale said the scoreline did not reflect her chances in the match.

“A couple of points could have gone either way that would have changed things but she played well when she needed to,” McHale said.

Elsewhere, Belgium’s Kim Clijsters won her first-ever Olympic match, just months before her scheduled retirement from tennis.

Clijsters swept past Italy’s Roberta Vinci 6-1, 6-4 in her tie and will now face either fifth seed Samantha Stosur of Australia or Spain’s Carla Suarez Navarro.

There were also wins for Urszula Radwanska of Poland, France’s Alize Cornet and China’s Shuai Peng.

In the men’s draw, Serbia’s Janko Tipsarevic eliminated Argentinian player David Nalbandian 6-3, 6-4, while Steve Darcis of Belgium upset former Wimbledon finalist Tomas Berdych 6-4, 6-4.

Slovakia’s Lukas Lacko made a name for himself at Wimbledon last month by beating Rafael Nadal, but was less fortunate in the first round of the Olympic tournament, losing 7-6, 6-1 to Germany’s Philipp Petzschner, who entered the draw as an alternate after Ivo Karlovic withdrew.