Matthew Ebden had not expected to last long against Novak Djokovic in the first round of the Olympics on Saturday and he was not wrong - but it left the Serbian wondering why the Australian doubles specialist was competing in the singles.

The 38-year-old effectively ruled himself out of the singles tournament as he battles a thigh injury picked up in training at Roland Garros, the scene of 14 of his 22 Grand Slam triumphs.

The Italian said he was "sad and disappointed" to drop out, adding that he had started feeling unwell on Monday after a practice week in Monaco.

The 37-year-old, a two-time Olympic champion, is planning to play in the singles and doubles at his fifth Games.

The 38-year-old Spanish left-hander has a protected ranking of ninth to put himself into the field for the Flushing Meadows fortnight, which begins on August 26.

"I don't have any limitations in my mind. I still want to keep going and play as long as I feel like I can play on this high level."

"So let's see if at the end of my career it's going to be 25, 30, 15, four (Slams). I don't know. All I want to say is I want to keep enjoying and let's see what the future brings to me."

"To all the fans that have had respect and stayed here tonight, I thank you from the bottom of my heart and I appreciate it," said an angry Djokovic.

"Of course, I didn't want to take his last match away from him. But at the end of the day I think a lot of the players in a similar situation would have done the same thing, prioritising their body."

The Spanish world number three came through 6-3, 6-4, 1-6, 7-5 against his 16th-ranked opponent to book a spot in the last-eight of a major for the ninth time in just 14 appearances.

On a cold and wet day at the All England Club, only three of the women's top 10 were left in the draw, while Andy Murray's Wimbledon career ended with a whimper when Emma Raducanu pulled the plug on their mixed doubles plans.

She left Manhattan with the world at her feet, but the problems that have dogged her since provide a cautionary tale about the pitfalls of sudden celebrity.

Seven-time champion Djokovic is chasing Roger Federer's record of eight titles at the All England Club and his 25th Grand Slam title in total.

Czech Vondrousova, who became the first unseeded woman to lift the title last year, earned a far less welcome accolade after a 6-4 6-2 defeat by Spain's Jessica Bouzas Maneiro.

Alcaraz, 21, beat Novak Djokovic to the title a year ago and has since taken his Grand Slam haul to three after winning the French Open earlier this month and despite being seeded three will be favourite to rack up number four.

Alcaraz, also the reigning Queen's champion, was beaten 7-6 (7/3), 6-3 by home favourite Jack Draper in the biggest win of the British number one's career.

Spanish tennis chiefs announced Wednesday that 22-time Grand Slam winner Nadal and newly crowned French Open champion Carlos Alcaraz would be part of the country's team at the Games next month.

"In Roland Garros, knowing all the Spanish players who have won this tournament and be able to put my name on that amazing list is something unbelievable," Alcaraz told reporters.

The world number one is just one match away from becoming the first woman to win the tournament in three straight years since Justine Henin in 2007 after a 6-2, 6-4 victory.

he injury, sustained in his fourth-round win over Francisco Cerundolo, ended the Serb's quest to win a record-extending 25th Grand Slam trophy and will result in him losing his top ranking to Italian Jannik Sinner on Monday.