Courtney Nguyen
WTA reporter on BBC Radio 5 live sports extra

Brady has zero main draw tour level wins and yet seven wins at the Grand Slams. This her second round of 16. This stat caught me off guard. It's a difficult one to explain.

She plays power tennis, which is an interesting one for Pliskova.

BBC Radio 5 live sports extra

We've got commentary available of this match and Rafa Nadal's fourth round match over on 5 live sports extra today.

You can listen using the player at the top of the page, or by clicking here. Go go go!

Gigi Salmon and Russell Fuller are raring to go.

American Jennifer Brady has made the most of her US Open opportunity this year.

Appearing in the main draw for the first time, she beat both the rain and Andrea Petkovic across two days before beating world number 25 Barbora Strycova.

She came close to losing against Monica Niculescu in the third round, but went on to win in three sets in a mammoth two hour 26 minute tussle.

It is only the third time in Brady's career that she has won consecutive tour-level matches. In fact, she thrives on the Slam pressure - her career record at majors is 7-3, while across other WTA events it's 2-11.

Image source, Getty Images

Pliskova has used her serve to get her out of trouble on several occasions at Flushing Meadows.

She's the WTA leader for aces delivered in 2017, having sent down 376 in 55 matches.

She's also served up 28 throughout this tournament so far - and, for every ace she serves at the US Open, she donates 200 euros to a children's hospital in Prague.

If I could put in the applause emoji, I would. It's a cracking gesture.

Image source, Getty Images

It's not been an easy run for Karolina Pliskova this far.

She began with a comfortable win against Magda Linette but had to come back from a first set loss to beat Nicole Gibbs in round two.

Her third round opponent Shaui Zhang looked to be a step too far, and the world number 26 had match point before Pliskova rallied.

In a stunning turn-around, she went on to win 3-6 7-5 6-4 and reach the fourth round for the second time.

Image source, Getty Images

Piers Newbery
BBC Sport at Flushing Meadows

After two days of gloomy skies and intermittent soakings, day eight is shaping up to be a beauty. The ground staff aren't wearing ponchos for the first time in three days and we are set to hit 27C later on, so no need for enormous eye-endangering branded umbrellas. Until tomorrow, apparently.

Image source, BBC Sport

The best match of the tournament went down last night on Arthur Ashe, when Petra Kvitova beat Garbine Muguruza in a two-set thriller.

Kvitova only returned to action in May after she was stabbed in the left hand by an intruder at her home, an injury which has required extensive surgery.

She overturned a 1-4 first-set deficit to beat the Wimbledon champ 7-6 (7-3) 6-3, sending down 24 winners to Muguruza's seven and kept her nerve in the final game to save three break points and advance to the quarter-finals.

And, as WTA writer Courtney Nguyen remarked on Kvitova's celebrations...

Right, here's how we're lining up today.

Following Karolina Pliskova and Jennifer Brady is world number one Rafael Nadal, who will take on Ukraine's Alexandr Dolgopolov.

They're followed by American Coco Vandeweghe and her clash with Lucie Safarova, before Roger Federer kicks off the night session against Philipp Kohlschreiber.

Finally, fourth seed Elina Svitolina takes centre stage against Madison Keys.

Image source, Getty Images

It's simple for Karolina Pliskova.

Reach the final at Flushing Meadows, and she's in with a shot at retaining her world number one ranking.

Lose today, and Garbine Muguruza or Elina Svitolina can sweep in to take her crown.

First up, though, is Jennifer Brady.

Image source, Getty Images