Now it's the turn of Serena Williams' compatriot Nicole Melichar-Martinez to try and get her team on the board.

And a smart volley from Erin Routliffe at the net gets them up and running, with a straightforward hold to 15. Solid.

There's still a whole lot of power behind that serve, let me tell you!

The 44-year-old Serena Williams nets to set up a pressure point at 15-30, but a 105 mile-per-hour serve helps her restore parity.

And how about that! A 113mph serve down the centre gets the crowd very excited, before Victoria Mboko wraps up the game with a smash.

Like she's never been away...

Emily Salley
BBC Sport at Queen's

"Serena Williams to serve," says the chair umpire.

That phrase probably used to strike fear into opponents' hearts.

Victoria Mboko and Serena Williams reach deuce on Erin Routliffe's serve, and here that means we will have a deciding point to complete the game.

Routliffe double-faults, and that is the perfect start for Mboko and Williams at Queen's!

Image source, Getty Images

Emily Salley
BBC Sport at Queen's

A raucous roar from the crowd as Serena Williams reacts quickly to smash home a vicious volley. It doesn't look like she's lost any firepower.

It is Victoria Mboko who will serve first in this match.

Both the Canadian and Serena Williams miss volleys at the net to leave them 15-30 down, but Williams' doesn't miss on the next couple!

The crowd are cheering each winner she hits louder and louder. Goodness knows what they'll be like an hour or so down the line.

Image source, Getty Images

23 major singles titles, a further 16 in doubles, four Olympic golds...

Some of these numbers are absolutely staggering.

Emily Salley
BBC Sport at Queen's

Janet, Carolyn and Jo have travelled from Oxford and they're soaking up the sun, as well as some Pimms, at Queen's today.

Janet said Williams is a "character" that "brings so much personality to the game, while Jo added: "She's just a legend in terms of tennis, she's just been there forever."

"A bit like we have," Carolyn jokes back.

Can she win this evening? "We're split over that," says Janet. "I think she'll be great, she'll be brilliant."

Annabel Croft
Former British number one on BBC TV

Serena Williams has totally stolen the headlines.

I can honestly say I never, ever dreamt in my wildest dreams that we would see her back out competing on a tennis court professionally again.

I'm intrigued as to where this is going to go. Four years is a long time out, she had a huge send-off at the US Open and her body was really hurting. She hasn't won a Grand Slam in singles since 2017. That's a very long time.

I guess Serena's right. Why not? I mean, it's certainly giving us something to talk about and something to really look forward to.

I'm very excited about seeing her out there.

Emily Salley
BBC Sport at Queen's

Here she is! A huge cheer and standing ovation as Serena Williams steps onto a tennis court for the first time in almost four years.

A wave to the crowd, but other than that there's no fuss. The 44-year-old limbers up and starts her warm-up.

Image source, Getty Images

Image source, Getty Images

Serena Williams says she has "nothing to prove" on her return to competitive tennis.

Her main motivation for taking that decision is the prospect of her daughters seeing her play again.

Williams gave birth to Olympia, now aged eight, in 2017 and went on to reach four major singles finals after returning to tennis a few months later. Her second daughter, Adira, was born in 2023 and has never seen her mother play on the tour.

But the American said she was not putting any pressure on herself as she returns to the sport that she dominated for so many years.

"I've had enough pressure. It's really about my kids getting to see me play," Williams said.

"It's also that being an athlete is the best thing that you can be in the highest place. Having an opportunity to still be able to possibly do that one last time is kind of cool and exciting."

Emily Salley
BBC Sport at Queen's

Image source, BBC Sport

Brian and Jill from Sussex have got the hottest tickets in town.

They are "very excited" to see Serena Williams play this evening. Although this won't be the first time they've watched the 23-time Grand Slam champion...

"We saw her when she was a very young girl at Wimbledon so it will be very nice to see her again," Jill said.

Brian added: "She was about 14 and her father had her out on the court practicing."

1375 days later, Serena Williams is back.

Huge cheers on Andy Murray Arena as the American walks out on to the court!

Emily Salley
BBC Sport at Queen's

Normally when a tennis match ends, you see fans flock out of the stadium to wait for the next one to begin.

Not today. Everyone on Andy Murray Arena has stayed glued to their seats. They don't want to miss Serena Williams' entrance.

Image source, Getty Images

It's almost time.

Serena Williams, the greatest women's player of the Open era, is about to make her competitive return after almost four years away from tennis.

The 44-year-old American great is teaming up with Canadian teenager Victoria Mboko in the women's doubles at Queen's, 196 weeks after her final appearance at the 2022 US Open.

They're taking on third seeds Erin Routliffe and Nicole Melichar-Martinez on Andy Murray Arena next!

It’s now 10 wins in a row for defending champion Tatjana Maria, who delivered another strong display to defeat Greece’s Maria Sakkari.

Image source, Getty Images

Defending champion Tatjana Maria faces Maria Sakkari on Andy Murray Arena in the day's third match.

Serena Williams' doubles match will follow.

British number three Katie Boulter on BBC Two after fighting back from trailing on Monday night: "First of all, thank heavens the clay season is over - we'd have been out there for four hours!

"I am really pleased with the way I came back today. I was a step slow last night and she was playing great.

"I had to respond and it's really hard to sleep at night when you're in the middle of a match but I managed to get a few hours and I am really pleased how I managed to turn it around.

"For me it's critical to start the grass season well. I started the year well on hard courts and was building momentum but I struggle on the clay courts - although I'm working hard to improve and I am very slowly - but here on grass I have an incredible crowd and am really grateful to be back here."