Novak Djokovic began his bid for a record 25th Grand Slam title and tied Roger Federer with his 89th match win at the U.S. Open by defeating qualifier Radu Albot of Moldova 6-2, 6-2, 6-4.

The second-seeded Djokovic, again wearing a gray sleeve over his surgically repaired right knee, was competing for the first time since claiming an Olympic gold medal three weeks ago at the Paris Games, the last significant achievement that was missing from his resume.

“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.

I haven’t had any official matches before the U.S. Open. So I’m expecting to be probably challenged a little bit more in the opening rounds,” he said.

“Hopefully, I can play better each day.” He said his knee, which was operated on in early June, feels fine.

Djokovic, a 37-year-old from Serbia, improved to 18-0 in first-round matches at Flushing Meadows and is now 89-13 overall at the hard-court tournament, which he’s won four times, including a year ago. He’s never lost earlier than the third round at the U.S. Open; Albot never has been past the third round in 30 appearances at majors.

The retired Federer went 89-14 in New York, with five consecutive championships from 2004 to 2008.

He’s the most recent man to win the U.S. Open at least twice in a row. Among men, only Jimmy Connors, who went 98-17, won more matches than Djokovic and Federer at the event.

Djokovic never has lost a Grand Slam match to someone ranked as low as No. 138 Albot. And Albot is now 0-12 against opponents ranked in the top 10.

Next up for Djokovic is a countryman, familiar opponent and friend, Laslo Djere, who advanced with a 6-7 (7), 6-1, 6-7 (7), 6-4, 6-2 victory over Jan-Lennard Struff. A year ago, Djokovic met Djere in the third round at the U.S. Open; Djere took the first two sets before Djokovic came through in five.

“It’s a guaranteed third round for one of the Serbian guys. Hopefully it’s going to be me. But Djere is a guy that really likes playing on a big stage.

I think he also loves the conditions here. It’s a bit quicker. Ball stays low. He has a very flat backhand particularly and very good serve, great return. He’s physically as fit as anybody,” Djokovic said. “I remember very well our match. It was a very tough match.

I’m going to try to analyze that and hopefully do some things even better than I did last year.