KEY BISCAYNE, Fla. 芒鈧珺次元官网网址� Milos Raonic has pulled out of the Miami Open after aggravating a right hamstring injury that sidelined him for nearly a month.

The No. 3-seeded Raonic withdrew before Sunday's match against American qualifier Jared Donaldson, who advanced to the fourth round.

Raonic said his injury became progressively worse after his opening match, his first since Feb. 25. He expects to be sidelined at least two weeks and perhaps longer.

The Canadian said he hasn't made it through an entire tournament healthy since Wimbledon last July.

In men's play, No. 2-seeded Kei Nishikori beat No. 25 Fernando Verdasco 7-6 (2), 6-7 (5), 6-1.

On the women's side, top-ranked Angelique Kerber lost the first three games and then rallied to reach the fourth round by beating American Shelby Rogers 6-4, 7-5.

Kerber replaced Serena Williams atop the rankings a week ago. Williams missed the tournament due to a left knee injury.

Svetlana Kuznetsova, who won Key Biscayne in 2006 and was the runner-up last year, beat American qualifier Taylor Townsend 6-4, 6-2. No. 10-seeded Johanna Konta defeated Pauline Parmentier 6-4, 6-0.

Steven Wine, The Associated Press