WIMBLEDON, England (AP) — Defending champion Serena Williams put on a serving clinic yesterday, hitting 20 aces in a straight-sets win over Dominika Cibulkova that set up a fourth-round match-up with former champion Maria Sharapova.

The top-seeded American had at least two aces in each of her eight service games and overpowered the 46th-ranked Slovak, 6-0, 7-5, on Centre Court.

“Serving that well feels awesome,” Williams said. “I serve well at Wimbledon for some unknown reason. I want to keep doing it. I wish I could serve like this every tournament.”

Williams won 37 of 43 service points and held at love five times. She won 19 of her first 20 service points, with Cibulkova putting only four returns in play in that stretch.

The 20 aces matched Williams’ total from last year’s semi-finals at Wimbledon, the highest number on record by a woman at the All England Club.

The first set lasted just 18 minutes, with Williams winning 25 of 31 points, serving six aces and hitting 12 winners. It was the third match in a row that Williams won the first set 6-0.

Cibulkova, a semi-finalist at the French Open last year, finally got on the scoreboard when she held serve for 1-1 in the second set. From then on, she kept the match competitive by holding serve, although she couldn’t cope with Williams’ serves.

Williams, chasing her fourth Wimbledon title and 13th Grand Slam crown, will face Sharapova tomorrow in a rematch of the 2004 final won by the Russian.

Sharapova served an ace on match point to beat Czech player Barbora Zahlavova Strycova, 7-5, 6-3. It was an uneven performance by Sharapova, who overcame 35 unforced errors and six double faults.

Also yesterday, third-seeded Caroline Wozniacki made it to the fourth round by beating Anastasia Pavlyuchenkova, 7-5, 6-4. She’ll face unseeded Czech Petra Kvitova, who upset 14th-seeded Victoria Azarenka, 7-5, 6-0.

Seventh-seeded Agnieszka Radwanska advanced with a 6-3, 6-1 win over Sara Errani of Italy. Other women winners were 9th-seed Li Na and Klara Zakopalova

In men’s play, sixth-seeded Robin Soderling beat the 24th-ranked Thomaz Bellucci 6-4, 6-2, 7-5, his third straight victory without losing a set.

Men’s winners included 9th-seeded David Ferrer and Frenchmen Jo-Wilfried Tsonga, Paul-Henri Mathieu and Julien Benneteau.