MELBOURNE, Australia (AP) — Eight-time Australian Open champion Novak Djokovic fended off Frances Tiafoe 6-3, 6-7 (3), 7-6 (2), 6-3 to reach the third round at Melbourne Park. The fourth set was on serve and appeared to be headed for another tiebreaker when Tiafoe was given a time violation on his serve. The 23-year-old American lost his temper and then his serve and didn’t win another game.

Dominic Thiem (teem), who lost the final last year to Djokovic but won the U.S. Open, took a short route to the third round with a 6-4, 6-0, 6-2 win over Donimik Koepfer.

Serena Williams kept her bid for a 24th Grand Slam singles title on track. She made only 11 unforced errors and dropped three games against Nina Stojanovic. But a 21st trip to Melbourne Park ended painfully for her older sister Venus, who landed awkwardly on her ankle as she approached the net for a volley against Sara Errani. Williams fought back tears before receiving treatment on the ankle, and gamely continued, hobbling between points, before losing 6-1, 6-0.

Naomi Osaka needed only an hour to sweep Caroline Garcia 6-2, 6-3.

Two top 10 players went out of the women’s draw: 2019 U.S. Open champion Bianca Andreescu, coming back from 15 months out with injury, was beaten by Hsieh Su-wei of Taiwan and ninth-seeded Petra Kvitova, a two-time Wimbledon champion and the 2019 Australian Open runner-up, lost to Sorana Cirstea.