Federico Gomez looks a little nervous but that will just settle them somewhat as he takes the hold to 30 in the opening game.

Qualifier Federico Agustin Gomez gets us started.

It's a maiden appearance in the main draw of the US Open for the 28-year-old.

Let's see how Jack Draper handles this one.

Jonathan Jurejko
BBC Sport senior tennis reporter at Flushing Meadows

Image source, Getty Images

If opponents thought Jack Draper looked like a 'UFC fighter' earlier this year, they might think the beefed-up Briton resembles a WWE wrestler now.

World number five Draper hit the gym in a recent training block, continuing his work to solve the physical issues which hampered his early days as a professional.

Even when Draper reached the US Open semi-finals last year, questions still remained over his durability.

Twelve months on, the 23-year-old Englishman has returned to the scene of his breakout Grand Slam run feeling stronger - and looking notably ripped.

"I have worked incredibly hard to improve my physicality on the court," said Draper.

"I think part of it is my genetics and growing into a bit more of a man's body. I think that took me a long time."

Jack Draper achieved his best result at a Grand Slam at last year's Flushing Meadows but arrives in New York this time with very little hard-court practice under his belt.

The British number one is still feeling the effects of an arm injury which forced him to pull out of the Canadian Open and Cincinnati Open - both key ATP tournaments leading up to the American major.

Draper did, however, return to the match court when he played alongside American Jessica Pegula in the new-look mixed doubles at Flushing Meadows.

While it did not look like Draper went full throttle on his serve as the pair reached the semi-finals, he said it was "perfect" preparation.

Image source, Getty Images

Jonathan Jurejko
BBC Sport senior tennis reporter at Flushing Meadows

Jack Draper arrived at the US Open without a competitive appearance under his belt since a shock early exit at Wimbledon in July.

But the time off court has allowed him to continue building up his base fitness during a training block in London.

There have been high-intensity sessions on a vertical cardio climber - a full-body workout gizmo which developers say is "one of the most effective and efficient ways of burning fat and calories".

"I've been leaving no stone unturned," Draper told BBC Sport.

"I've been doing a lot of leg strength, a lot of cardio work and a lot of versa-climber.

"Ultimately, I'm doing stuff where you're shocking your body all the time and working it as hard as possible to get the best gains."

In his early days on the ATP Tour, Draper was seen as lightweight and prone to quitting matches because of physical problems.

But Draper demonstrated he was a different beast during the Australian Open in January, outlasting three successive opponents in gruelling five-set matches.

Brilliant stuff from Sebastian Korda.

He saves two set points and wins four points in a row to keep hold of his serve.

If Cameron Norrie wants to win this second set, he'll have to serve it out himself.

Image source, Getty Images

Daniel Kiernan
Former British tennis player on BBC Radio 5 Sports Extra 2

I wouldn't have had this one down as a tight match really.

Renata Zarazua is an incredible professional who is difficult to beat if you're not playing well because she is always going to show up.

Madison Keys saved those two set points in incredible fashion and she has done that repeatedly this year. She has pulled through with her back against the wall, whether that's set point down or match point down.

Sebastian Korda hits a fizzing backhand to save the first set point, before Cameron Norrie nets a return.

It's deuce.

Victory in just one hour and 23 minutes for Barbora Krejcikova means we'll be seeing British number one Jack Draper very soon.

He takes on Argentine Federico Agustin Gomez in his opening-round match next on Louis Armstrong.

Here we go...

Madison Keys is living dangerously. A double fault from the American, who then sees her forehand drive bounce off the net and land wide to give Renata Zarazua two set points.

Keys saves the first with a brave backhand right on the sideline, and then wins the next three points to force a tie-break.

A more difficult hold for Cameron Norrie as Sebastian Korda looks to break back.

But the Briton holds to 30, to put himself within a game of tying up the second set.

Mexican Renata Zarazua is soaking up Madison Keys' power impressively and redirects a fierce forehand to edge ahead in the set.

The New York crowd are trying to get behind the American sixth seed with shouts of encouragement as she once again has to serve to stay in the set.

Sebastian Korda looks to be moving a lot better than he was a couple of games ago following that medical timeout.

A very quick service game from the American puts Norrie back on serve.

Another solid service game from Cameron Norrie.

He's yet to drop serve in this match.

He holds to 15 to maintain his break lead in this second set.

Image source, Getty Images

Daniel Kiernan
Former British tennis player on BBC Radio 5 Sports Extra 2

That is a statement result for Barbora Krejcikova. It was woman against girl out there. It will put a bit of respect on her name and warn others to not look at her seeding. It was a very routine win.

It is great to see her back to this level of form. I would expect she is in a pretty good place to have a good run this year in New York.

Sebastian Korda's serving is well below the standard it was at during the first set, when it was causing Cameron Norrie all sorts of trouble.

Nevertheless, the American holds to keep himself within a break of the Briton.

Daniel Kiernan
Former British tennis player on BBC Radio 5 Sports Extra 2

This match is becoming a game of cat and mouse.

Cameron Norrie has slowed the tempo down really nicely and is prolonging the points, so it's taking big winners for Sebastian Korda to win points at the minute.

If you're going to go toe-to-toe with Norrie and turn this into a gladiatorial battle, Korda has to see his game plan through and cannot disappear at the end of the first set and beginning of the second set, as he has.

World number 82 Renata Zarazua claws her way back from 15-30 to win her service game, and sixth seed Madison Keys must now hold her serve to stay in the first set.

"You're playing further behind the baseline than her [Zarazua] right now," says Keys' coach and husband Bjorn Frantangelo as the Australian Open champion looks disconsolate after another error.