Aegon Championship: Nick Kyrgios retires injured after first set against Donald Young

London: Nick Kyrgios retired with an injury after losing the opening set 7-6 (3) to Donald Young in the first round at the Queen's grass-court tournament on Monday, the latest setback for the Australian player.

The ninth-seeded Kyrgios slipped at the back of the court during the second point of the ninth game, with the score at 4-4. He required treatment on his left hip and continued playing, despite not moving freely in hot conditions in west London.

After losing the tiebreaker, Kyrgios headed straight for his bag, put away his racket, shook hands with Young and walked off.

Kyrgios, who could be a doubt for Wimbledon starting on July 3, said in the build-up to the match that he has had hip trouble for the last seven months but was now playing without pain. He also has been troubled with soreness in his right shoulder and began the match on Centre Court with strapping round his right knee.

He shouted in pain, clutched his hip and covered his face with his hands while lying on the ground following his fall, which came after he was wrong-footed by a shot from Young.

"It's rough to see him go down like that, especially on surfaces like grass and clay - it's not for sure certain footing," said Young, the No. 55-ranked player from the United States. "I'm not going to act like I'm happy to get through that way, but at the end of the day I'm happy to be through to the second round as well."

It has been a difficult season for Kyrgios, who has been battling injury and also took a short break from tennis in April following the death of his grandfather.

Earlier, fifth-seeded Jo-Wilfried Tsonga beat Adrian Mannarino 6-2, 6-2, and sixth-seeded Grigor Dimitrov - the winner of this Wimbledon warmup in 2014 - looked impressive in defeating Ryan Harrison 6-3, 6-1.

"Every moment counts, every practice," said Dimitrov of the short grass-court season.

On Court One, seventh-seeded Tomas Berdych beat Steve Darcis of Belgium 7-5, 6-3.

Defending champion Andy Murray plays his opening match on Tuesday, against fellow Briton Aljaz Bedene. The event has a strong field that has been weakened by the withdrawals of French Open champion Rafael Nadal and Juan Martin del Potro.