Beatriz Haddad Maia reached the last eight of last year's US Open, her best ever run at the event. She lost to Karolina Muchova in her quarter-final.

The 29-year-old from Brazil, ranked 22nd in the world, is the 18th seed at this year's tournament.

Haddad Maia throws in a double fault in her opening service game but then fires down an ace to wrap up a hold to 30 against Britain's Sonay Kartal.

Katie Boulter gets off to a solid start, hitting four first serves to get the ball rolling on Grandstand Stadium.

Tough task for Katie Boulter today against 27th seed Marta Kostyuk. The Brit to serve first.

* denotes server

Image source, Getty Images

Also getting under way shortly, British number three Sonay Kartal kicks off her US Open campaign against 18th seed Beatriz Haddad Maia on Court 12.

Kartal arrives in New York off the back of a first-round exit at the Cincinnati Open earlier this month, but will take comfort in already defeating her opponent 6-2 6-1 at Indian Wells earlier this year.

The 23-year-old Briton also comes in off the back of her career-best Grand Slam performance, reaching the Wimbledon fourth round in July.

If Kartal comes through her opening match, she will take on Roland Garros semi-finalist Lois Boisson or Switzerland's Viktorija Golubic in the second round.

Image source, Getty Images

It's been a tricky summer for Katie Boulter but the 29-year-old Briton is feeling upbeat as she prepares to face 27th seed Marta Kostyuk of Ukraine in the first round of the US Open.

Boulter lost four consecutive matches for the first time in four-and-a-half years between June and mid-August but stopped the rot with a win in Cleveland last week, and says a break at the end of July helped refresh her.

"I really feel like I regrouped and started building again," said the world number 48. "And I feel like I'm in a much better place even than I was on the grass now. I kind of found myself again, which is really important."

Boulter hasn't been beyond the second round of a Grand Slam since she reached the third round at Flushing Meadows two years ago.

But the British number two did beat Kostyuk in their only previous meeting, which came in the final in San Diego in March last year, when Boulter claimed the biggest title of her career to date.

British players have a 100% winning record at this year's US Open so far, with Emma Raducanu, Jack Draper and Cameron Norrie all successfully making it through their first-round matches.

Five more British players - Katie Boulter, Sonay Kartal, Francesca Jones, Jacob Fearnley and Billy Harris - will be aiming to join them in round two today.

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Listen to live commentary of the US Open via the link at the top of this page, on BBC Radio 5 Sports Extra 2 and on BBC Sounds.

So what happened yesterday? Let us fill you in.

In the women's singles draw, we've seen a huge upset with Australian Open champion Madison Keys suffering a first-round defeat by Mexico's Renata Zarazua in three sets.

Tennis waved goodbye to a legend as two-time Wimbledon champion Petra Kvitova played the last match of her career, losing in straight sets to France's Diane Parry.

And former Wimbledon champion Barbora Krejcikova ended Victoria Mboko's hopes of a fairy-tale run at the US Open following a breakout year for the teenager while Elena Rybakina handed a harsh lesson to 16-year-old Grand Slam debutant Julieta Pareja.

Over in the men's draw, British number one Jack Draper is safely through to round two despite being taken to four sets by Argentine qualifier Federico Gomez.

Compatriot Cameron Norrie reached the second round after injured opponent Sebastian Korda was forced to retire.

Second seed Carlos Alcaraz also made a winning start in New York with victory over American opponent Reilly Opelka.

A whole host of first-round matches are coming your way this afternoon.

Britons Sonay Kartal and Katie Boulter are up first soon as they take on Beatriz Haddad Maia and Marta Kostyuk respectively.

Compatriot Francesca Jones will also make her main draw US Open debut when she takes on German Eva Lys.

Over in the men's draw, Jacob Fearnley and Billy Harris will also be in first-round action. That could be much later but we'll keep you updated.

Away from the Brits, Wimbledon champion Iga Swiatek is in action first on Arthur Ashe before men's champion Jannik Sinner takes to court. Home player and former champion Coco Gauff takes to court in the evening session.

Wimbledon finalist Amanda Anisimova also gets her campaign under way before Naomi Osaka takes to Louis Armstrong in the night session.

Welcome to day three of the US Open.

Two Brits sailed through to round two yesterday. Five more are in action today.

Let's do this.