And the second break point is saved from Williams. Although a double fault gives Ahn a third chance for a break early on.

Serena Williams unleashes a powerful volley at the net to see off the first of those two break points. One gone, one to go. 30-40.

Double break point for Ahn in game three. 15-40.

Image source, Reuters

A half chance for an early break for Williams as an Ahn double fault saw the score at 15-30, but Ahn recovered to hold on to her serve.

The roof is open now on Philippe Chatrier after it had been closed early on with a smattering of spectators inside.

There had been plans to have 11,500 fans at the French Open - 5,000 on Court Philippe Chatrier, 5,000 on Court Suzanne Lenglen and 1,500 on Court Simone Mathieu.

However, with coronavirus cases on the rise again in France, that has now been capped to just 1,000 on Philippe Chatrier.

Still, good to see anyone in attendance after the US Open was played behind closed doors.

The most routine of holds to love, ending the opening service game with an ace and Williams is up and running at this year's French Open.

Image source, Reuters

Here we go. Serena to serve first.

Some quotes from Serena Williams, who says: "I'm here so I wouldn't be playing if I didn't think I could perform.

"I'm not at 100% physically but I don't know any athlete that performs physically perfectly."

On reaching the semi-finals at the US Open earlier this month, she adds: "A semi-final is great but is it great for me? Absolutely not.

"I'm in a position where I can't be satisfied. I don't want to say I'm happy [at reaching the semi-finals] because I'm not."

Image source, Getty Images

On to today...

Serena Williams and Kristie Ahn will know each other's game well as this is their second Grand Slam match in September as they met in the first round of the US Open earlier this month.

Williams took the victory, winning 7-5 6-3.

Kristie Ahn, 28, is the world number 102, although she has been as high as 87th in the rankings. This is her first ever match at the French Open - and has one of the toughest tasks possible.

Williams is currently ninth in the world, but seeded sixth, and aiming for her fourth French Open title after winning it in 2002, 2013 and 2015.

It was also bad news for British hopes in the women's event too...

British number one Johanna Konta's hopes of another deep run at the French Open were ended by American teenager Coco Gauff in the first round.

Konta, 29, lost 6-3 6-3 to the talented 16-year-old, who put in an assured performance in her first Roland Garros main draw appearance.

A 2019 semi-finalist, Konta was error-prone against a youngster tipped by many pundits as a future major winner.

Konta's was the third British singles defeat of the opening day in Paris.

Her loss followed exits by Andy Murray and Dan Evans on a cool day in the French capital that drew complaints about conditions from some players, as the tournament got under way four months later in the year than usual.

But former world number one Mats Wilander has questioned whether Murray, ranked 111th in the world, should have been handed a wildcard.

Wilander said: "I think Andy Murray needs to stop thinking of himself and start thinking about who he was. Does he have a right to be out there taking wildcards from the young players?"

Australia's Nick Kyrgios was not impressed and tweeted this...

Earlier today, Stan Wawrinka tweeted this message about Andy Murray...

Andy Murray was in a reflective mood after his first-day opening round defeat.

"I should be analysing that hard and trying to understand why the performance was like that," said Murray.

Murray's match was played under floodlights on an open Court Philippe Chatrier on a chilly Parisian night, but he said the conditions were not a factor in his below-par performance.

"I don't feel like that's a valid reason," said Murray, who will next play at two indoor events being held in Cologne next month.

"Maybe to not enjoy the matches as much when it's like that, but not in terms of it affecting your performance in any way. I need to have a long, hard think about it.

"It's not for me the sort of match I would just brush aside and not give any thought to."

Image source, EPA

Andy Murray's return to the clay proved to be a chastening experience as he lost in straight sets to Stan Wawrinka in the French Open first round.

The 33-year-old Scot was well below the level of 2015 champion Wawrinka, who eased to a 6-1 6-3 6-2 victory.

Murray's exit came after British number one Dan Evans lost to Japan's Kei Nishikori in a fluctuating five-setter.

Evans has lost on all three appearances in the main draw at Roland Garros after a 1-6 6-1 7-6 (7-3) 1-6 6-4 defeat.

British number three Cameron Norrie and qualifier Liam Broady are left to carry the flag in the men's singles.

We have two Brits in singles action later on and yesterday was a tough day for British tennis fans.

We have BBC Radio 5 Live Sports Extra commentary from Roland Garros so press play at the top of this page to listen to our team, which includes Russell Fuller, David Law, Naomi Cavaday and Miles McLagan.

These are the matches we will be keeping across over the next few hours.

Court Philippe Chatrier

• Kristie Ahn (US) v Serena Williams (US, 6)
• Egor Gerasimov (Blr) v Rafael Nadal (Sp, 2)

Court Suzanne Lenglen

• Elina Svitolina (Ukr, 3) v Varvara Gracheva (Rus)
• Gael Monfils (Fr, 8) v Alexander Bublik (Kaz)
• Daniil Medvedev (Rus, 4) v Marton Fucsovics (Hun)

Court Simone Mathieu

• Tamara Zidansek (Slo) v Garbine Muguruza (Spa, 11)
• Kamil Majchrzak (Pol) v Karen Khachanov (Rus, 15)

Court Seven

• Iga Swiatek (Pol) v Marketa Vondrousova (Cze, 15)
• Zhang Shuai (Chn) v Madison Keys (US, 12)

Court 10

• Jiri Vesely (Cze) v Liam Broady (GB)
• Daniel Galan (Col) v Cameron Norrie (GB)

Court 14

• Angelique Kerber (Ger, 18) v Kaja Juvan (Slo)
• John Millman (Aus) v Pablo Carreno Busta (Spa, 17)

Hello and welcome along to BBC Sport's coverage of the second day of the French Open. We've got a busy day ahead.

Image source, Getty Images

Serena Williams has been the French Open champion three times and another success over this next fortnight will bring her level with Margaret Court's total of 24 Grand Slam triumphs.

Can this be a history-making two weeks for Williams? She begins her campaign today.