Serena Williams defeated Elena Vesnina 6-3, 6-1 to reach the second round of the Madrid Open on Monday while defending champion Petra Kvitova advanced after beating Marina Erakovic 6-2, 6-3 in her opening match.

The ninth-seeded Williams fired 13 aces and 40 winners against Vesnina, who was struggling with her game on the slippery blue clay court. The Russian lost her balance in the sixth game and set up a break point for Williams, who pulled ahead to lead 4-2.

Williams' ninth ace of the match provided a set point for the ninth-ranked American to take the first set and wrap up the match against the 68th-ranked Russian in just over an hour.

Good start

"I'm feeling good but I wasn't thrilled,'' Williams said.

"This is my first tournament in Europe so hopefully I will just keep my good form and just keep going,'' she added.

Williams will face Russia's Anastasia Pavlyuchenkova in the second round.

Kvitova also needed an hour to defeat Erakovic of New Zealand. The Czech player saved all three break points against her while converting four herself.

Also on Monday, Andrea Hlavackova, Ekaterina Makarova, Lucie Hradecka, Lucie Safarova and Sara Errani won their first round matches at Madrid Open.

In the men's tournament, Spain's Nicolas Almagro rallied to beat Santiago Giraldo of Colombia 6-7 (5), 6-3, 6-3.

Almagro saved four set points before hitting long to lose the first set in a tiebreaker. The thirteen-ranked Spanish player broke his opponent in the opening game of the second after adjusting his game to the new court surface to win the match in three sets.

"The court isn't very good, it's very slippery,'' Almagro said of the unorthodox blue clay court that has been criticised by players after it was introduced for the first time in this year's tournament.

Other winners Monday included Serbia's Victor Troicki, Mikhail Youzhny of Russia and American Ryan Harrison. who beat Sergiy Stakhovsky of Ukraine, 7-6 (3), 7-6 (5) to reach the second round.