Moment of shock in the round of 16: Coughing attack in the middle of the match: Zverev swallows fly - Boris Becker jokes on TV

He then returned to the court and hit an ace. "It doesn't taste so good, but maybe he should do it more often if he hits an ace afterward," said tennis legend Boris Becker jokingly as an expert on Eurosport.

Tennis star Alexander Zverev easily reached the quarterfinals of the French Open. Last year's finalist benefited from an injury to his opponent Tallon Griekspoor in Paris. The Dutchman was forced to retire after just 51 minutes with the score at 6-4, 3-0. Zverev could now face a clash with record Grand Slam champion Novak Djokovic . The Serb will face Briton Cameron Norrie in his round of 16 match today.

Zverev only had a few problems at the beginning on Court Suzanne-Lenglen. The 28-year-old got off to a weak start and dropped his first service game. Zverev was exposed early on by the Dutchman with several drop shots, appeared dissatisfied, and quarreled with his team in the stands.

But then the world number three found his focus and recovered from the early 0-3 deficit. Griekspoor, who Zverev beat in a fifth-set tiebreak last year at Stade Roland Garros, appeared ailing and repeatedly grabbed his abdominal muscle during breaks. A large bandage became visible when Zverev swapped shirts.

After about 40 minutes, Zverev took the first set. Even after that, Griekspoor seemed weak and quickly lost his serve. Then the Dutchman was unable to continue, and Zverev quickly advanced to the quarterfinals.