Seven-time Wimbledon champion Serena Williams is out of the tournament after being forced to retire through injury ©Getty Images

Seven-time Wimbledon champion Serena Williams is out of the tournament after being forced to retire through injury in round one, whereas fellow grass-court icon Roger Federer benefitted from a withdrawal to overcome a scare in the men's singles draw.

American Williams took to Centre Court at the London venue with heavy strapping on her right leg, and after slipping on more than one occasion versus Belarus' Aliaksandra Sasnovich retired with the score 3-3 in the first set.

Numerous players have commented on the greasiness of the playing surface, with others also slipping. 

Williams had been seeded sixth in the women's singles and this was seen by many as her best chance to draw level with the divisive Australia Margaret Court on 24 Grand Slam singles titles.

Williams, now 39, had already pulled out of the Olympics.

Court's Open-era record was achieved in a time when few international players contested the Australian Open.

The present-day star of Australian tennis, Ashleigh Barty, was pushed to three sets by Spain's Carla Suárez Navarro, who was diagnosed with Hodgkin Lymphoma in 2020 but following treatment has made a short-lived return to top-level tennis.

The top seed ultimately triumphed 6-1, 6-7 (1-7), 6-1.

French Open champion Barbora Krejčíková of the Czech Republic beat Danish teenager Clara Tauson in straight sets.

Seventeen-year-old American Coco Gauff, German Angelique Kerber - a three-time Grand Slam winner - and eighth seed Karolína Plíšková of the Czech Republic also enjoyed two-set wins.

In the men's singles, Swiss great Federer was 6-4, 6-7 (3-7), 3-6, 4-2 down against Adrian Mannarino when the Frenchman slipped and picked up a knee injury.

Federer went on to win the fourth set, after which Mannarino retired hurt.

"I hope he recovers quickly and we see him back on the courts," eight-time Wimbledon champion Federer said afterwards.

"He could have won the match, he was the better player.

"I got lucky."

Top-10 seeds Daniil Medvedev, Alexander Zverev and Denis Shapovalov all won through to round two.

Whereas Germany's Zverev was a straight-sets victor, second seed Medvedev needed four to see off German Jan-Lennard Struff.

Canada's Shapovalov found the going harder still against another German, but eventually beat Philipp Kohlschreiber 6-4, 4-6, 6-3, 5-7, 6-4.