MADRID (AP) — Defending champion Serena Williams beat Maria Sharapova 6-1, 6-4 in the final of the Madrid Open on Sunday to retain her No. 1 ranking and collect her 50th career title.

With the top ranking at stake, Williams stormed out to an early lead as Sharapova struggled with her serve.

The second-ranked Russian briefly recovered her poise in the second set, but Williams' form never wavered as she eased to the title.

Williams improved her record against Sharapova to 13-2. Her two losses came in 2004.

It was Sharapova's first loss in a red-clay final after winning eight in a row.

In the men's final later Sunday, Rafael Nadal plays Stanislas Wawrinka of Switzerland.