NEW YORK: Top seed Novak Djokovic has been starved of competitive action at the US Open but on Sunday the world number one feasted on unseeded Briton Kyle Edmund in a 6-2 6-1 6-4 romp that put him into the quarter-finals.

Djokovic had a second-round walkover as Czech Jiri Vesely withdrew due to injury, and was leading 4-2 in his third-round match when Russian Mikhail Youzhny retired with a leg ailment, making it six days since his last full match.

The Serb kept himself busy on the practice courts but was happy to cut loose against an actual opponent, making 21-year-old Edmund the target of his arsenal of rifled groundstrokes, angled volleys, pinpoint passing shots, lobs and drop shots.

"Feels great to play a match," Djokovic said in an on-court interview. "I haven't played much tennis.

"Baseline shots, both forehand and backhand, were working very well. Think I was most pleased with that."

After two lopsided sets that Djokovic totally controlled, Edmund made the third set competitive, holding for 4-4 before the Serb closed out the set to end the match.

Djokovic's victory put him into the last eight against ninth-seeded Frenchman Jo-Wilfried Tsonga, a 6-3 6-3 6-7(7) 6-2 winner against American 26th seed Jack Sock.

The world number one, who was bothered by a left wrist injury that may have been a factor in his third-round exit from Wimbledon and first-round loss at the Rio Olympics, had his right arm and elbow area treated during a medical timeout at 2-1 in the third set against Edmund, but Djokovic downplayed it.

"I needed a little bit of massage," he said of treatment similar to that which he received during his opening-round match against Jerzy Janowicz of Poland.

"I feel great at this moment physically; mentally as well. I'm motivated. So coming into the second week of a grand slam quarter-finals ... it's exactly where I want to be."

Edmund, who entered the tournament ranked 84th and upset 13th seed Richard Gasquet of France in the first round and 20th-seeded American John Isner in the third , was playing his first match at Arthur Ashe Stadium.

"Just enjoyed the experience," the South African-born Briton said. "It was obviously a tough match.

"Just a lot of learning to do from it, which is a really good thing. To play the world number one on the biggest tennis court in the world, doesn't get much better than that."

"It's been a great tournament for me. Loads and loads of positives."