Britain's Jamie Murray is into a second set tie-break now...

Partner Bruno Soares is on serve but Koepfer and Ruusuvuori have set point at 6-4.

Alexander Zverev isn't too flustered. He's got the first set in the bag and he holds comfortably to draw level at 1-1 early in the second.

Swiss 11th seed Belinda Bencic is performing well. She's moved 4-1 up in the second.

Iga Swiatek has work to do. Has the frustration of losing that tie-break knocked her a bit? It seems that way.

Britain's Dan Evans said he "got a good, healthy lesson" after being outclassed by second seed Daniil Medvedev in the last 16.

Evans lost 6-3 6-4 6-3 to the Russian 2019 runner-up, who is yet to drop a set at Flushing Meadows.

"He was a different level to me today," Evans, 31, said.

Asked what he had learned from the encounter, the Briton replied with a smile: "You're looking at the draw hoping he's nowhere near me for the rest of my days."

Image source, Getty Images

Ooh, here we go.

Belinda Bencic has broken early in the second set, after taking that lengthy first-set tie-break.

She leads Iga Swiatek 7-6 3-1 and will now serve to try and retain that break.

Image source, Getty Images

Former world number five Daniela Hantuchova believes Emma Raducanu will win a Grand Slam title in her career and be ranked inside the top five "within a year".

"More people are starting to believe Emma is Grand Slam material - that's how good she is already," Hantuchova said on Amazon Prime.

"I hope Coco Gauff is watching what Emma is doing because she is on another level as far as everything goes.

"If she stays healthy and has the right people around here she can be top five within a year. I don't think I'm exaggerating there. She is the full package."

There's little separating Britain's Jamie Murray and Bruno Soares against German Dominik Koepfer and Finland's Emil Ruusuvuori.

They are heading to another tie-break in the second set.

It's still tight as anything in this enthralling match between seeds Belinda Bencic and Iga Swiatek.

They remain on serve in the second set.

13th seed Jannik Sinner holds on. Alexander Zverev has a chance to serve out the set though.

First set point for Alexander Zverev on Jannik Sinner's serve but he clips the net.

It's back to deuce.

Jamie Murray isn't the only Briton in doubles action. Joe Salisbury is alongside partner Rajeev Ram of the USA and they have just taken the second set against Croatia's Ivan Dodig and India's Rohan Bopanna.

Salisbury and Ram, the fourth seeds, lost the first set in a tie-break.

German fourth seed Alexander Zverev is going along smoothly. He's backed up the break and holds to move 5-3 up.

Italian Jannik Sinner to serve next.

Image source, Getty Images

It's a pretty big day for British teenager Emma Raducanu.

She faces home favourite Shelby Rogers on Arthur Ashe Stadium - the world's biggest court - in the last 16.

It's her first overseas Grand Slam and she hasn't dropped a set in New York.

She thrashed Spain's Sara Sorribes Tormo in the third round but this could be her biggest test yet.

World number 150 Raducanu will face the last remaining American woman in the cavernous 24,000-capacity main court.

Rogers also knocked out top seed Ashleigh Barty on the weekend.

Britain's Jamie Murray and Brazilian partner Bruno Soares are in men's doubles action.

They have taken the first set in a tie-break against German Dominik Koepfer and Finland's Emil Ruusuvuori.

It remains on serve in the second set.

German fourth seed Alexander Zverev is currently taking on Italian Jannik Sinner over on Arthur Ashe.

He's got the early break and is serving to hold at 3-2.

Wow! Belinda Bencic has taken the first set after a gruelling tie-break which finished 14-12 in her favour.

She needed five set points - and denied Iga Swiatek with four of her own - to take the longest set to be played at the US Open so far.

Understandably, Swiatek is hugely frustrated. Still all to play for

Here are some of the biggest matches taking place in the men's and women's singles today/tonight.

Arthur Ashe:

• Alexander Zverev v Jannik Sinner
• Shelby Rogers v Emma Raducanu
• Novak Djokovic v Jenson Brooksby
• Maria Sakkari v Bianca Andreescu

Louis Armstrong:

• Belinda Bencic v Iga Swiatek
• Oscar Otte v Matteo Berrettini

Grandstand:

• Karolína Pliskova v Anastasia Pavlyuchenkova

Right now there's a real battle taking place over on Louis Armstrong as Swiss 11th seed Belinda Becic and seventh seed Iga Swiatek from Poland are in a first set tie-break.

It's currently 12-12! I'll keep you updated with that match over the next hour.

Good evening!

We've got a cracking night in store at the US Open. Britain's Emma Raducanu is playing for a place in the quarter-finals.

World number one Novak Djokovic is also in action, while there's some British interest in the men's doubles.

Grab a brew, we're in for a big night.