'Aging' Djokovic calls for earlier starts after late-night opener

Midnight matches may be popular with fans but not with old campaigner Novak Djokovic, who bemoaned a late night at the start of his U.S. Open title defence on Monday.

A rusty Djokovic beat qualifier Radu Albot 6-2 6-2 6-4 to reach the second round but the two-hour and seven-minute match stretched until midnight at Arthur Ashe Stadium.

The pair were unable to take to the court until late due to Clara Burel's comeback win over Sloane Stephens, who crumbled in three sets after leading 6-0 3-0.

"Well, I don't think that aging helps really staying so late and playing very late," 37-year-old Djokovic told reporters.

"I can feel, you know, my batteries are low now. I'm shutting down.

"But it's been a long wait, to be honest. I thought I'm going to go out on the court, like, 8:15 p.m. because Stephens was 6-0 3-0 serving and then all of a sudden it turns out to be a two-and-a-half hour match or whatever.

"You just have to accept it, I guess .... I like playing night matches, but I love to start first.

"So hopefully I get more chances to play at night and am scheduled first so we can start at a more decent time and finish at a more decent time.

"I guess for the fans there is something special about late-night finishes, particularly post-midnight. For us, I don't know. It's not really what you want but if you get a W (win), then it's all good."

Djokovic returned to the court for the first time since winning a long-coveted Olympic gold medal in the singles at Paris.

Though easily accounting for Moldovan journeyman Albot, Djokovic's lack of warmup matches showed as he served up 10 double-faults and racked up nearly twice as many unforced errors as winners.

"It's always challenging to start, particularly when you haven't played on this surface for five, six months and coming off an Olympic gold and playing on clay," he said.

"I'm expecting to be probably challenged a little bit more in the opening rounds.

"The good thing about Slams is you have a day between matches where you can train, where you can really work on things and perfect your game. That's what I need."