So...mixed results for the Brits so far with a win for Toby Samuel and defeat for Cameron Norrie. Let's see how Katie Boulter gets on now.

She's up next on court five, followed by fellow Brit Jacob Fearnley.

Pat Cash
Former Wimbledon champion on BBC Radio 5 Live

That very last point sort of summed up the match - just a very good solid first serve, got into a rally, nice opportunity short ball for Norrie and he just missed it. Time and time and time again it just wasn't a Cam Norrie performance.

In many ways he set the point up beautifully but it was just one of those days where you can't finish it off.

It wasn't a technical match Norrie would have been worried about, you have got to execute. Van Assche has played a lot of matches of late and he was just rock solid.

This is Toby Samuel's first main-draw win at a Grand Slam.

The 23-year-old, who began this year ranked outside the world's top 250, came from a set down in each of his three qualifying matches to get here but had no such issues today against Tomas Machac.

Waiting for him in round two is another Czech in 18th seed Jiri Lehecka, who beat Pablo Carreno Busta in four sets.

Long from Cam Norrie.

Match point, Luca Van Assche.

Pat Cash
Former Wimbledon champion on BBC Radio 5 Live

There was nothing on about five of those forehands from Van Assche in that last game but, such is Norrie's confidence, he's just missing those type of shots. The balls that are bouncing mid-court and shoulder height, his bread and butter if he was in form.

What has Cam Norrie got left here?

He's shown great spirit to keep in touch with Luca Van Assche, but he has been outplayed since the first set.

The Briton lets out another huge yell after levelling at 15-15, and has hope after his opponent double-faults for 30-30.

Tomas Machac gifts a couple more points away to present Toby Samuel with two match points.

Image source, Getty Images

Cameron Norrie is getting himself fired up for the fight here, letting out a big roar as he moves to game point after Luca Van Assche reached deuce.

The Frenchman responds with a fizzing forehand into the back corner to haul Norrie back, though, and the still-quiet Van Assche shakes his fist after watching his opponent blast wide.

Norrie is the first to blink in an extended baseline exchange, and it leaves Van Assche a game away.

Shanked forehand. Tomas Machac led 2-0 in the third set. He's now trailing 5-2, with Toby Samuel - on his US Open debut - serving for a spot in the second round.

Tomas Machac is his own worst enemy. At 30-all, he gets down low to cushion a drop shot... and pops the ball in the net.

Two break points saved, five deuces navigated. Toby Samuel extends his lead. Phew.

Toby Samuel is on the back foot, defending for all he's worth as Tomas Machac - with a second break point - pummels deep return after deep return. But his resistance pays off, with the Czech eventually losing his composure and posting a forehand long.

Luca Van Assche dusts himself down after the disappointment of losing his advantage in this set and gets back on track with a hold to love.

Just two more games needed as far as the Frenchman is concerned - but Cameron Norrie has shown in the past few minutes that he still has enough to ensure it is not quite that simple.

Tomas Machac isn't going down without a fight. He recovers from 30-0 down to force deuce, unleashing a tracer bullet forehand with Toby Samuel on game point.

He couldn't capitalise on his break point but he's forced a fourth deuce on Samuel's serve, firing a cross-court backhand winner with the Briton rushing the net.

The shouts of "allez" have returned on Cameron Norrie's side of the court.

There's a spring in his step and he's making his winners now, lifting a lob over Luca Van Assche to level the fourth set at three games apiece.

It's a funny old game.

One minute Cameron Norrie's race appeared to be run, the next Luca Van Assche's level suddenly drops and the Briton is back in the set.

Still, there is a lot of work to do here.

Image source, Getty Images

Tomas Machac pulls one point back but then fires an uncontrolled forehand well into the tramlines.

From 2-0 down, it's all looking quite rosy again for Toby Samuel. Big service game coming up to consolidate the break.

Oh, hold on a minute!

I don't think anyone sat around the court expected this game from Luca Van Assche. A double fault gifts Cameron Norrie two break points and a huge lifeline here.