And another cross-court backhand from Danielle Collins levels up at deuce.

The second straight service game she's been taken to deuce but again she emerges triumphant as Serena Williams dumps a couple of shots into the net.

From 0-40 down, that's a heck of a hold from Collins.

A stunning backhand baseline winner saves one break point and a serve into Serena Williams' body brings Danielle Collins' deficit back to 30-40.

All of a sudden, Serena steps it up.

A backhand return brings up three break points.

But the Williams serve proves too potent a weapon on the following two points, Collins unable to muster much of a return on either.

Another hard-fought game though.

Dismissive.

Danielle Collins just swipes a return across the court to level at 30-30 on Serena Williams' opening service game.

It looked routine when she forged 40-0 up but it took a couple of deuces for Danielle Collins to get over the line there.

Serena Williams will be disappointed with a couple of loose returns that gave that opening game away a little bit after she fought so hard to get back in it.

A lovely forehand winner to the corner from Serena Williams forces deuce.

If this opening game is any indication, we're in for a heck of a ride here. Hard-fought and evenly-matched.

Laura Robson
Former British number one

Collins is such a great competitor - she went to college in the States.

The years of grinding it out make her really feisty on the tour.

Danielle Collins whistles a backhand around the post to go 30-0 then ends a rally with a fine winner.

But Serena Williams fights back to take the next two points...

We are under way, Danielle Collins serving first.

And she wins the opening point as Serena Williams' return goes long.

The players are warming up on Court Philippe-Chatrier and the roof has just been re-opened.

The previous game on the showpiece court, between Alexander Zverev and Laslo Djere, was played under the roof after rain began to fall.

Image source, Getty Images

She not be quite as widely known as her more illustrious and fellow American opponent today but Danielle Collins is fully capable of springing an upset on Court Philippe-Chatrier this afternoon.

The 27-year-old from Florida is currently ranked 50th in the world but rose as high as 23 a couple of years ago after reaching the semi-finals of the Australian Open.

She has form at Roland Garros too, making the quarter-finals last year and upsetting former world number one Garbine Muguruza on the way.

Collins also beat current world number one Ashleigh Barty in Adelaide in February - can she knock off another superstar of the sport today?

BBC Sport

If it's audio delight rather than the written word you're after, fret not - the BBC Radio 5 Live tennis team has live commentary of our all-American encounter.

Simply click the icon at the top of the page to listen in to their online only commentary - Russell Fuller, Iain Carter and Laura Robson are on the mikes.

There will also be live commentary on BBC Radio 5 Live of tonight's night match between Stefanos Tsitsipas and John Isner. That's scheduled to begin at 20:00 BST.

The loss of so many top women's seeds - six of the top 10 have exited the tournament already with the opening week not yet over - has opened up certain sections of the draw.

Earlier on Friday, third seed Aryna Sabalenka departed the quarter of the draw featuring Serena Williams and Danielle Collins - but it still looks arguably the toughest section.

This afternoon's winner must face 21st seed Elena Rykabina before a quarter-final against either Sabalenka's conqeuror Anastasia Pavlyuchenkova or two-time Australian Open champion Victoria Azarenka.

Image source, Getty Images

There's already been a notable shock on one of the show courts on Friday as third seed Aryna Sabalenka was toppled in three sets by Anastasia Pavlyuchenkova on Simonne Mathieu.

Two-time Grand Slam champion Victoria Azarenka is up next for Pavlyuchenkova in the last 16 after the 15th seed produced a very impressive 6-2 6-2 victory over American Madison Keys.

Elena Rybakina awaits the winner of our featured match between Serena Williams and Danielle Collins after she beat Elena Vesnina while Tamara Zidansek recovered from losing the opening set 6-0 to beat fellow unseeded player Katerina Siniakova.

Read our round-up here.

The two Americans have met only once - and it will be a match that is very much fresh in the memory, having come only four months ago.

Serena Williams was the victor on that occasion but only narrowly, edging Danielle Collins out in a tie-break at the Yarra Valley Classic in Melbourne in February.

Image source, Getty Images

It's been more than four years since Serena Williams captured the most recent of her 23 Grand Slam titles - the Australian Open in 2017.

And the question of whether the American great can equal Margaret Court's record of 24 Slam wins looms larger than ever.

The clay of Paris has always seemed the unlikeliest source of a record-equalling triumph but a win today will put the 39-year-old into the last 16.

She's up against compatriot Danielle Collins in an all-American affair - and we have live text coverage for you right here.