Are Coco Gauff, Naomi Osaka or Novak Djokovic in danger at the Australian Open?

Novak Djokovic vs. Tomas Machac

“Another three-hour match, back to back against the youngsters,” Djokovic said after his four-set, second-round win over 21-year-old Jaime Faria, which came two days after his four-set win over a 19-year-old qualifier.

If Djokovic sounds proud of his stamina at 37, he has a right to be. But he’ll likely want to clean up the rest of his game a little against the 24-year-old, 26th-seeded Machac.

The Czech is not only young, he can bash a ball from the baseline with the best of them, including Djokovic. They’ve played twice, both matches have gone three sets, and each man has won once. In the seven months since they last faced each other, Machac has shown even more upside; in Shanghai last October, he outhit and upset Carlos Alcaraz.

Two things may help Djokovic. Traditionally, the third round is when he begins to put his game in cruise control at the Slams. The early, ragged, four-set wins turn into more polished straight-setters. And while Machac is 13 years younger, he’s coming off a long, five-set struggle with Reilly Opelka.

Machac is a dangerous opponent for Djokovic, but I’m not ready to bet on him winning over best of five. Winner: Djokovic