Serena Williams

The 23-time Grand Slam champion, who is warming up for the Australian Open, was at her dominant best after a slow start in which she saved four break points in the opening game of the contest at Margaret Court Arena.

Former world number one Williams has not played since withdrawing from last year's French Open second round in September with an Achilles injury, but made quick work of Gavrilova, striking 27 winners including 16 in the opening set.

The American, who turned 39 this week, had been due to play Bulgarian Tsvetana Pironkova in the second round later but after a warm-up decided the injury was too severe.

Williams, a three-time former champion at Roland Garros, said she may not play again this year.

Williams had suffered the problem during her semi-final loss to Victoria Azarenka in the U.S. Open and said ahead of her Roland Garros campaign that she was not at 100% physically but had recovered sufficiently to play.

American Williams, 38, stopped Rus serving out the match at 6-5 before winning 7-6 (8-6) 3-6 7-6 (7-0) in almost three hours.

Rus, ranked 72nd in the world, became edgy as a memorable win loomed and it was costly.

"It was a real physical match," said 23-time Grand Slam champion Williams.

"I played pretty well, I was being aggressive and hit some good shots, but she just kept fighting."

The two-time champion will play Greece's 13th seed Maria Sakkari in the third round.

Not since winning the 2017 Australian Open had Williams clinched silverware – the 23-time grand slam champion a runner-up at Wimbledon (2018 and 2019) and the US Open (2018 and 2019), while she retired in the 2019 Rogers Cup final.

However, Williams ended her drought by defeating fellow American Jessica Pegula 6-3 6-4 in the women's final in New Zealand.

The women's singles draw has seen a plethora of surprise results, with none of the top 10 seeds reaching the quarter-finals, a turn of events that has seen 23-time grand slam champion Williams become the favourite to win the Venus Rosewater Dish for an eighth time.

And she ensured there would not be another shock in Monday's contest on Centre Court, her seemingly unstoppable march to the final continuing with a 6-2 6-2 triumph.

Serena won 7-6 7-5 against Kiki Bertens before Venus won 6-3 6-4 against Sorana Cirstea to tee up a third-round clash.

That will be their earliest meeting at a tournament since the first match they ever played - a second-round tie at the 1998 Australian Open.

Serena's first-round win earlier this week was her first victory since a 14-month absence after giving birth. She leads her elder sister 17-11 in all-time meetings.

Elsewhere, US Open finalist Madison Keys was eliminated by wildcard Danielle Collins, the world No 116.

Williams beat Zarina Diyas of Kazakhstan 7-5 6-3 in her first-round match at Indian Wells.

The 23-time Grand Slam singles champion said: "It definitely wasn't easy but it was good. I'm a little rusty but it doesn't matter. I'm just out here on this journey doing the best I can."

In her straight-sets win, Williams hit 27 unforced errors and 34 winners in front of a large crowd in California.

Williams played aggressively and broke Diyas five times in the match that lasted 92 minutes.

Williams is a vocal advocate of women's rights and empowering women, but Murray is concerned that the players driving through changes in the sport are male and that the women's game could be left behind.

From Billie Jean King to Venus Williams, who was a key figure in securing equal prize money at all the grand slams, female players over the past 50 years have not been afraid to get political.

Murray was one of several to voice exasperation last week when plans to radically transform the Davis Cup made no mention of the Fed Cup, a competition in need of reform.

Williams returned to tennis earlier this month after spending nearly a year away from the sport in order to give birth to her first child.

However, the 39-time Grand Slam winner believes she is "lucky to have survived" her pregnancy after suffering a pulmonary embolism shortly after giving birth.

The 36-year-old was named in the American team last month, along with sister Venus, and it was expected the siblings would play singles at the match in North Carolina.

However, the team announced on Friday that Saturday's opening singles would feature Venus and CoCo Vandeweghe, who will face Arantxa Rus and Richel Hogenkamp respectively.

As things stand, Serena has been named in Sunday's doubles match when she will partner Lauren Davis against Lesley Kerkhove and Demi Schuurs.