After his US Open title defence was cut short last year because of injury, perhaps an easy first week was exactly what Rafael Nadal needed.

On the other hand, it could leave the second seed underprepared for the tougher times ahead as he almost invisibly slipped into the round of 16.

“You never know what’s better or worse, no?” 18-time grand slam champion Nadal said.

He was back on the court Saturday for the first time in five days, beating Hyeon Chung 6-3 6-4 6-2 to reach the fourth round for his 13th-straight grand slam tournament.

Nadal hadn’t played since Tuesday, when he beat John Millman in straight sets in the opening round, after he got an unscheduled night off Thursday when Thanasi Kokkinakis had to pull out with a shoulder injury.

The Spaniard has spent only slightly more than four hours on court through the first eight days of the tournament.

“But for me personally, in some way, I will prefer to play the match,” Nadal said.

“In some way is true that you save energy. So you never know what’s the best thing.”

Nadal is not drawn to face world No.1 Djokovic or Roger Federer until the final but the next tasks are by no means easy either.

He next plays 2014 champion Marin Cilic and then possibly sixth-seeded Alexander Zverev in the quarter-finals.

Cilic, the 22nd seed, mixed 21 aces with an astonishing 17 double faults in his 7-5 3-6 7-6 (8-6) 6-4 win over 14th-seeded John Inser.

On Louis Armstrong Stadium, Zverev toughed out a 6-7 (4-7) 7-6 (7-4) 6-3 7-6 (7-3) victory over Slovenian Aljaz Bedene in a match that lasted more than three-and-a-half hours.

The German will next play Argentine Diego Schwartzman after the 20th seed rolled past Tennys Sandgren 6-4 6-1 6-3.

French 13th seed Gael Monfils outlasted Denis Shapovalov 6-7 (5-7) 7-6 (7-4) 6-4 6-7 (6-8) 6-3 to advance to a meeting with unseeded Spaniard Pablo Andujar, who beat Alexander Bublik of Kazakhstan 6-4 6-3 6-2.