Federer advances in Miami Open

Roger Federer did not lose a serve as he beat Juan Martin del Potro 6-3, 6-4 to advance to the fourth round of the Miami Open in Key Biscayne, Fla.

Federer plays again Tuesday against 14th-seeded Roberto Bautista Agut, who needed three sets to top Sam Querrey. Other third-round men’s winners included top-seeded Stan Wawrinka, eighth-seeded David Goffin and 10th-seeded Tomas Berdych.

Top-seeded Angelique Kerber made the women’s quarterfinals after beating Risa Ozaki 6-2, 6-2. Kerber next meets 11thseeded Venus Williams, who defeated seventh-seeded Svetlana Kuznetsova 6-3, 7-6 (4) in a matchup of Miami Open champions.

Williams fended off two set points to get into the tiebreaker, and then rallied from 4-1 down in that decider.

Caroline Wozniacki reached the quarters when sixth-seeded Garbine Muguruza retired after the first set after feeling dizziness that she said was brought on by the heat. Wozniacki, the 12th seed, took that set over Muguruza 7-6 (1).

“Happy to be in the quarters,” Wozniacki said. “I feel like I’m playing well.” Hockey: Fourteen U.S. senators wrote a letter to USA Hockey’s executive director over their concerns about the treatment of the women’s national team. The senators, all Democrats, urged David Ogrean to resolve the matter and ensure the team receives “equitable resources.” They cited the Ted Stevens Olympic and Amateur Sports Act.

The U.S. is the defending champion at the International Ice Hockey Women’s World Championship, which begins Friday in Plymouth, Mich. Softball: Annie Aldrete homered for the second straight day as host Cal (20-8, 3-3 Pac-12) completed a three-game sweep of Stanford (16-13, 0-3) with a 7-1 romp.