Defending champion Novak Djokovic made short work of Spain's Roberto Carballes Baena to reach the second round at the US Open.

The world number one and top seed, bidding for a 17th grand slam title, won 6-4 6-1 6-4 in just under two hours.

"It's great to be back," said Djokovic, who has never lost in the first round at Flushing Meadows.

"I'm obviously grateful that at this stage of my life and my career that I'm still able to play at this level on this special court.

"I've never faced Carballes Baena before, he's solid from the back of the court so I'm pleased with my performance.

"Obviously getting out of the blocks takes a bit of time, but in the first set I had some break points and managed to capitalise on the big moments. I know what I need to do, to keep going."

Daniil Medvedev is Djokovic's likely quarter-final opponent and the fifth seed from Russia cruised past Prajnesh Gunneswaran.

Medvedev, who beat Djokovic on his way to winning in Cincinnati earlier this month, won 6-4 6-1 6-2.

Japan's Kei Nishikori, the seventh seed, had an easy passage after Marco Trungelliti retired injured in the second set.