Serena Williams remains on track for a seventh Wimbledon title after seeing off Germany's Annika Beck in the third round on middle Sunday.

The American top seed won 6-3 6-0 on a Centre Court filled with spectators enjoying a surprise extra day's play following a week of rain.

Williams will next play Russian 13th seed Svetlana Kuznetsova, who beat Sloane Stephens 6-7 (1-7) 6-2 8-6 .

All the fourth-round matches will be played on Monday.
'I know what it takes to win' - Serena

Beck, who beat Britain's Heather Watson in the first round, broke for a 2-1 lead against Williams but was then brushed aside.

Williams powered through 11 of the next 12 games and dropped only four points in an utterly dominant second set.

"It felt good," said the world number one.

"I wasn't sure what the stats were obviously, but on that last service game, I was thinking, 'Have I lost on my first serve yet?'

"I wasn't sure, but I just tried to stay focused. It gives me a lot of confidence. I know what it takes to win these tournaments. It's just about now just doing it."
Russians quartet through to round four

Kuznetsova fought back from 5-2 down in the final set to beat Stephens and the 31-year-old former French and US Open champion will not be overawed by facing Williams.

Despite being on the wrong end of a 9-3 record against the American, Kuznetsova beat Williams in Miami earlier this year.

"It's a great thing to play Serena in Wimbledon," said Kuznetsova. "It's a great match. I'm really happy about it. She will be the favourite but I enjoy playing these kind of matches."

Middle Sunday proved to be a successful day for Russian players, with Anastasia Pavlyuchenkova, Ekaterina Makarova and Elena Vesnina also progressing.

Makarova beat Czech Barbora Strycova 6-4 6-2 to set up a last-16 meeting with Vesnina, who saw off American Julia Boserup 7-5 7-5.

Pavlyuchenkova defeated Swiss Timea Bacsinszky 6-3 6-2 and will next face American Coco Vandeweghe, who beat Italian sixth seed Roberta Vinci 6-3 6-4.

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