Serena, a seven-time Wimbledon champion, is still one shy of Margaret Court's Grand Slam singles record of 24.

Williams remains in the top 10 in the world but bowed out early in the French Open and the days of her holding a psychological edge over players appear to have gone.

Eight-time winner Federer, like Williams edging closer to his 40th birthday, had a disappointing second round exit at Halle -- his traditional warm-up for Wimbledon which he has won 10 times.

He starts against Frenchman Adrian Mannarino who has reached the fourth round at Wimbledon three times.

Federer says his longevity was not something he planned.

"Truthfully, I don't think my goal was to play till, whatever, 39 or 40 or more," he said.

"It was maybe more like 35 I was thinking, which was already a high number at the time."

Federer lost an epic final to Novak Djokovic two years ago despite holding two championship points.

Last year he underwent two knee surgeries.

- 'Big X on my back' -

Williams faces Aliaksandra Sasnovich of Belarus on Tuesday.

The American has never lost a first round match at Wimbledon, posting a 19-0 record.

Indeed, she has only ever lost one opening round match in 78 major appearances.

The American puts players generally being able to play longer down to technology.

"I think technology has played a huge role in that," she said.

"The way we view the game, the way we recover, the way our shoes are made, the way the equipment is made.

"Because normally people retire at 29, 30, before -- 29, 30, 32 was the max.

"I feel like there's several players at that age who are just hitting their stride."

Williams, though, acknowledges that with her legend status every player who faces her ups their game.

"I've had a big X on my back since '99, since I won the US Open," she said.

"When players play me that hard every single tournament, every single match, every single Grand Slam, it just doesn't matter where, you just get better.

"Yeah, it's been difficult mentally when someone might beat you and they lose directly in the next round almost every time."

One of the big barriers to Williams's goal of equalling the controversial Court's record will be Ashleigh Barty.

The 25-year-old world number one has the honour -- in the absence of 2019 champion Simona Halep -- of opening on Centre Court against Carla Suarez Navarro.

The 32-year-old Spaniard is likely to have the crowd on her side after being diagnosed and then beating Hodgkin's lymphoma.

Barty will be seeking to add senior Wimbledon glory to her 2011 junior title with the added symbolism of it being 50 years since her fellow indigenous Australian Evonne Goolagong Cawley won her first Wimbledon title.

Barty will be wearing an outfit inspired by Cawley's iconic scallop dress she wore when she won in 1971.

"It's a really special anniversary for a lot of Australians, but for indigenous Australians in particular," said Barty of the 50th anniversary of Cawley's triumph.

Only 32 of the scheduled 64 singles matches were completed Monday.

Tuesday's bumper programme also includes second seeded Russian Daniil Medvedev, fresh from his first grass court title in Mallorca, facing Jan-Lennard Struff.

The German player defeated Medvedev in Halle earlier this month.

Coco Gauff, who made the last 16 in 2019 as a 15-year-old qualifier, is seeded 20 and faces British wildcard Francesca Jones.

Venus Williams, the five-time winner, faces Romania's Mihaela Buzarnescu while French Open champion Barbora Krejcikova tackles Clara Tauson of Denmark.

Also on the schedule is Australian crowd-pleaser Nick Kyrgios who plays France's Ugo Humbert.

Popular

PDI-P will likely be part of opposition: Ganjar

Indonesia one step from Olympics after beating South Korea

Bahlil leads task force to boost sugar, bioethanol production in Papua