When it comes to facing world No. 1 Novak Djokovic, what's the toughest task?

"Everything," says Diego Schwartzman.

Djokovic: Play Best-of-Three Sets Everywhere

The top-seeded Djokovic launched his quest for a record-tying sixth ATP Finals crown sweeping Schwartzman 6-3, 6-2.

Afterward, the eighth-seeded Argentinean was asked to address the toughest thing about Djokovic.

"Everything is difficult against him," Schwartzman said of Djokovic. "I think what he's doing when he's playing his best, he's moving the ball from everywhere to everywhere, you know, to every single point on court."



Schwartzman said Djokovic's skill transitioning from defense to offense poses major problems for opponents.

"It's very difficult to see or to know what he's going to do and trying to make good points, because he's moving the ball, he's doing defenses, he's doing winners," Schwartzman said. "He has a lot of talent when he have the chance to move the ball."

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