Djokovic struggles, but into semis

Before the first set ended on Tuesday, Novak Djokovic (in pic) 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. “The first set and a half, he was dominating from the baseline,” Djokovic said. “I was frustrated and nervous and wasn’t showing composure on the court.”

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 after the second set and lost 36 of the final 41 points.

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. “Too many errors, and I was going for it the whole match,” Williams said. “Toward the end, I just never found the happy medium between being aggressive and putting the ball in the court.” Williams is a three-time Key Biscayne champion, but her most recent title came in 2001. 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. Djokovic received a warning for ball abuse early, 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. After the second set, trainer bandaged Dolgopolov’s soles. He moved poorly after that and won only three of 27 points.