PARIS — Hitting sublime backhands, defending champion Stan Wawrinka surged to a 7-6 (7-5), 6-7 (7-9), 6-3, 6-2 win and into the French Open quarterfinals Sunday, so in control against Viktor Troicki that he amused himself and the crowd by hitting with a ball boy while Troicki got treatment in the third set.
After lending the boy a racket for their impromptu hitting, Wawrinka, seeded third, got back to business, securing his win in cold, humid conditions in just under three hours.
Also through to the quarters: second-seeded Andy Murray, in a rain-interrupted 7-6 (11-9), 6-4, 6-3 victory over big-serving American John Isner.
Wawrinka needed eight set points to overcome Troicki, seeded No. 22, in the first set. In the second-set tiebreaker, Troicki needed five set points to break down Wawrinka, who hit an attempted forehand lob long for Troicki to pull even at one set each.
A backhand winner from Wawrinka — one of 14 from him in the match — broke Troicki to love in the fourth game of the third set, during which Troicki got treatment on his right leg and was given pills, and Wawrinka made the ball boy's day.
"I was a little bit bored, was waiting for (Troicki), was talking to the ball kid," Wawrinka said. "I asked him if he was playing tennis. I said, 'Okay, let's play.' "
An ace brought up two match points for Wawrinka, and he converted the first when Troicki netted a backhand from the baseline.
Albert Ramos-Vinolas, a 55th-ranked, unseeded Spaniard who had never made it past the second round of 18 previous Grand Slam tournaments, ousted No. 8 Milos Raonic 6-2, 6-4, 6-4 to play Wawrinka in the quarterfinals.
The cool, cloudy weather appeared to take some bite out of Raonic's serve on the red clay as new coach John McEnroe watched before they work together at Wimbledon next month.
On the women's side, Garbine Muguruza advanced to the quarterfinals for a third straight year. The array of shots and maturity the 22-year-old deployed in an intensely fought 6-3, 6-4 win against 2009 champ Svetlana Kuznetsova strengthened the argument that Muguruza could soon be challenging Serena Williams for the top spot .
Standing in the way of her second semifinal at a major tournament is Shelby Rogers. The 108th-ranked American, who had never made it out of the third round at a Grand Slam, beat Irina-Camelia Begu 6-3, 6-4. The Romanian, seeded No. 25, is the third seeded player to fall to Shelby in her march to the quarterfinals.
At night, rain halted play again, and after about 20 minutes, with the rain still beating down and night falling, organizers halted play for the day. Unfinished were fourth-round matches between Simona Halep and Sam Stosur, and Tsvetana Pironkova and Agnieszka Radwanska.