Gibbs is flying. The aces were expected to come from the Pliskova racquet in this match but the American hits two spinning serves beyond the world number one.

Gibbs has hit 13 winners and just three unforced errors so far. Pliskova on the other hand is struggling for rhythm.

She needs to find it quick. The world number one is a game away from losing this first set.

Dimitrov is playing so deep behind the baseline against Rublev but he comes tippy-toeing forward to muller Rublev's second serve.

The Russian holds, though, before Dimitrov races through his own service game to hold to love, complete with back-to-back aces. Lovely stuff - he's a game away from the first set.

There was a fascinating match first up on Louis Armstrong this morning.

French Open champ Jelena Ostapenko coughed up five double faults in one service game against Sorana Cirstea, but saved three break points in the same game to take the first set.

It's not been the most vintage exhibition of tennis, with the combined error count reaching 51, along with 19 double faults from both players, but Ostapenko has muscled her way through.

It's the first time she's reached the third round at Flushing Meadows. Up next is either Daria Kasatkina or Christine McHale.

Image source, Getty Images

Ouch. This start will now start to worry the world number one.

She falls a double break behind with a horrible service game that includes three double faults. Horrid.

I'll just put this out there. The last time I did a live text on a women's world number one was at the French Open when Angelique Kerber lost in the first round...

Simon Cambers
Tennis journalist at Flushing Meadows

Pliskova is bending and stretching a little. She's maybe not feeling absolutely 100%. It's hard for players to be 100% for every match - in fact, it's almost impossible.

Break of serve very well backed up.

Gibbs is playing really well. Her high ranking opponent plays one of her better points of the match but the American sprints along the baseline and hits a cross court forehand out of Pliskova's considerable reach.

The sparse crowd are loving what they're seeing from their player so far.

Image source, Reuters

It's taken a little over 15 minutes for Grigor Dimitrov to make inroads on Andrey Rublev's serve.

He was pushing the Russian in the opening game and he broke at the second time of asking in the third game, forcing Rublev to overwork the forehand by the finest of margins. The seventh seed has promptly backed up the break with a speedy hold.

Simon Cambers
Tennis journalist at Flushing Meadows

Wozniacki has a pretty good point. It would be very hard for the US Open not to put Sharapova on a main court she is box office, no matter what you think of the decision to give her a wildcard. I would have more of an issue with the way the schedule was yesterday, with Eugenie Bouchard first on Arthur Ashe. She's had a terrible season and that should not have been near the main court. Wozniacki and Makarova should have had that spot.

Caroline Wozniacki was not impressed with the scheduling during yesterday's mammoth 87-match day.

Speaking to Danish newspaper Ekstra Bladet, Wozniacki described the decision to schedule Maria Sharapova's US Open matches on the main stadium court as "questionable".

"I understand completely the business side of things and everything, but someone who comes back from a drugs sentence and, you know, performance-enhancing drugs, and all of a sudden gets to play every single match on centre court, I believe is a questionable thing to do," the fifth seed said.

"I think it doesn't set a good example."

Image source, Getty Images

There's the early break for Gibbs!

World number one Pliskova looks a little edgy after saving the fourth break point of the game as she nets a drive volley.

That brings up another opportunity for the American and this time Gibbs takes it. As Simon says below she is wearing heavy strapping on left thigh but there are no signs of a problem so far.

An electric start from the American.

Simon Cambers
Tennis journalist at Flushing Meadows

It's clear the strapping on Nicole Gibbs isn't hindering her movement. She's defending and moving well. Pliskova has a lazy, languid looking style but it's very effective. There's so much power there.

This is a very promising start from American Nicole Gibbs.

The short right-hander is looking to take the ball on and hits a beautiful backhand winner to bring up two break points.

Pliskova saves those break points but here is another. Gibbs scampers left and right around the court to get back into a rally and eventually the world number one nets.

Break point Gibbs...

A few early blows have been traded over on Louis Armstrong, but it's still on serve.

A delightful floated backhand from Dimitrov takes him to 40-15, and he holds with a big serve thar Rublev whacks into the net.

I gave the first serve the big build-up and Karolina Pliskova did not disappoint.

She started and ended the first game with an ace as she made a solid enough start.

American Gibbs hit back confidently in the second game in the second game to level at 1-1.

Image source, Getty Images

On paper this one looks a tough one for Nicole Gibbs.

Her win over world number 75 Cepede Royg was just her fourth at tour level this season although she did reach round three of the Australian Open in January.

Victory today would be the biggest of her career. She has a 0-6 record against top 10 players in her career.

Image source, Getty Images

Our first focus today will be on women's world number one Karolina Pliskova.

The big-serving Czech may not be as well known as others who have reached the top of the rankings in recent years but she rightly comes in as one of the favourites.

She reached the final here last year and has won three tournaments so far in 2017 with Elina Svitolina the only player to have won more with five.

The ace counter will also get a work out today. Pliskova has hit 348 in 52 matches so far this season, more than anyone else.

She has won two of the three matches she has played against today's opponent Nicole Gibbs but the American will certainly have a rowdy Arthur Ashe crowd on her side.

I say that but the pair have just got under way in the New York sunshine and Ashe is by no means full. More in a sec...

Grigor Dimitrov is next up on Louis Armstrong Stadium, with the seventh seed and Russia's Andrey Rublev currently going through the warm-up motions.

Before the tournament started, he was waxing lyrical about the emotional impact of his favourite movie - The Notebook.

He's word perfect in one of the movie's most emotional moments - spoiler alert, folks, external - but he watches it on his own because he doesn't want people to see him crying.

Bless.

Image source, AFP/Getty Images

Simon Cambers
Tennis journalist at Flushing Meadows

There's a big hole in the bottom half of the men's draw. There's a massive opportunity for some of the qualifiers to come through and have the best run they've ever had.

Image source, Getty Images

As I mentioned earlier day three at Flushing Meadows was err.... busy.

Due to the earlier rain, there were 87 matches to get through with Kyle Edmund leading the British charge deep into the New York night.

He kept British hopes alive by beating American Steve Johnson 7-5 6-2 7-6 (7-4). Fellow Britons Aljaz Bedene and Cameron Norrie were knocked out, leaving Yorkshire's Edmund as the last Briton standing in the draw.

Elsewhere, men's fourth seed Alexander Zverev suffered a shock defeat to Croatia's Borna Coric while Maria Sharapova battled through to the third round on her Grand Slam return.

Nicest man in tennis Juan Martin del Potro is second on Grandstand, facing Adrian Menendez-Maceiras of Spain.

He's followed by Gael Monfils and Svetlana Kuznetsova, who play Donald Young and Kurumi Nara respectively.

Sixth seed Dominic Thiem is third on Louis Armstrong Stadium as he plays Taylor Fritz, follwed by Madison Keys' meeting with Tajana Maria.

Tomas Berdych is first on court 17, playing Alexandr Dolgopolov and for British interests, Jamie Murray plays his first doubles match with Bruno Soares on court six.

Murray Sr is also in action with Martina Hingis in the mixed doubles later in the day.

Image source, Reuters