KEY BISCAYNE, Fla. — Before the first set ended Tuesday, Novak Djokovic had busted a racket in anger, drawn jeers from the crowd and received two code violations, which cost him a point penalty. There were no further outbursts, and as Djokovic's play improved, so did his mood. He rallied from a break down in the second set and beat Alexandr Dolgopolov 6-7 (3), 7-5, 6-0 in the fourth round of the Miami Open. Dolgopolov led 4-1 in the second set before Djokovic mounted a comeback to remain in contention for his fifth Key Biscayne title. Dolgopolov required treatment from a trainer after the second set and lost 36 of the final 41 points. Djokovic received a warning for ball abuse early in his match, and when he netted a forehand to fall behind 5-4, he slammed his racket against the concrete to earn a second code violation. The crowd hooted as he walked to his chair, and Djokovic raised both arms in response. “That was a gesture of just feeling bad for what I have done,” Djokovic said. “I was fighting a battle inside of myself, I would say. That was the biggest battle that I fought today.” Venus Williams' recent resurgence stalled when she lost in the quarterfinals to No. 12-seeded Carla Suarez-Navarro 0-6, 6-1, 7-5. The 34-year-old Williams was broken six times in the final two sets and double-faulted twice in the final game. Williams is a three-time Key Biscayne champion, but her most recent title came in 2001. Her sister, seven-time champion Serena Williams, will play in the quarterfinals Wednesday against No. 27 Sabine Lisicki. With Rafael Nadal already eliminated and Roger Federer skipping the tournament, the No. 1-seeded Djokovic's most likely opponent in the final would be No. 3 Andy Murray, who became the ninth active man to win 500 matches by beating Kevin Anderson 6-4, 3-6, 6-3. The milestone made Murray's victory especially sweet. Afterward he was presented with a cake large enough to feed many of the players he has beaten. Murray will face unseeded Dominic Thiem in the quarterfinals, while Djokovic will play No. 6 David Ferrer. No. 22 John Isner, the last American in the men's draw, reached the Key Biscayne quarterfinals for the first time by outlasting No. 5 Milos Raonic in a serving duel, 6-7 (3), 7-6 (6), 7-6 (5). Isner, who has yet to be broken in three matches, next faces No. 4 Kei Nishikori, who beat No. 18 David Goffin 6-1, 6-2. Nishikori has lost 10 games in his three matches. Others advancing included unseeded Juan Monaco and No. 8 Tomas Berdych, who won when No. 17 Gael Monfils fell, hurt his right hip and retired in the second set. In other women's play, No. 9 Andrea Petkovic swept No. 14 Karolina Pliskova 6-4, 6-2. Murray plays again Wednesday, while Djokovic is off until Thursday. — AP
