Fifth seed Alexander Zverev overcame a tough challenge from South African Kevin Anderson to reach the US Open second round with a 7-6 (7-2) 5-7 6-3 7-5 win.

"Kevin is not somebody you usually play in the first round," Zverev said. "I'm extremely happy to get through."

Greece's Stefanos Tsitsipas, the fourth seed, also reached the second round.

Both players are chasing a maiden Grand Slam title with defending champion Rafael Nadal absent from the men's draw due to coronavirus concerns while 20-time major champion Roger Federer is not playing because of knee surgery.

But they must still compete with men's top seed and 17-time Grand Slam champion Novak Djokovic, who faces Damir Dzumhur in his first-round match after 00:00 BST on Tuesday.

Zverev broke serve to go 3-2 up against Anderson in the first set but was later broken back by the world number 117, managing to claim victory in a tie-break.

Anderson broke late in the second set to level things and pushed the German at every opportunity with his dominant serve, but Zverev eventually wrapped up the match in just over three hours.

Tsitsipas, 22, sailed through his opening match, beating Spain's Albert Ramos Vinolas 6-2 6-1 6-1.

The world number six will face either American Maxime Cressy or Slovakia's Jozef Kovalik in the second round, while Zverev plays American 19-year-old Brandon Nakashima.