German sixth seed Alexander Zverev is already 3-0 up in his match over on Louis Armstrong. He's up against Slovenian Aljaz Bedene.

Canadian 15th seed Bianca Andreescu, 19, beat former Australian Open champion Caroline Wozniacki 6-4 6-4 in a match featuring 10 service breaks.

Andreescu will face American Taylor Townsend in the next round after the world number 116 beat Romanian Sorana Cirstea 7-5 6-2.

But Dutch seventh seed Kiki Bertens lost 6-2 6-3 to German Julia Gorges, seeded 26th. She will face Donna Vekic in the fourth round after the Croat beat Kazakh Yulia Putintseva 6-4 6-1.

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But the world number 170 cannot save the second.

A long rally, but it's Chung Hyeon who drives a backhand narrowly wide and Rafael Nadal gets the breakthrough.

Rafael Nadal is forced deep behind the baseline and can't pick up a backhand slice.

First break point saved by Chung Hyeon.

Chung Hyeon punches long and looks frustrated. That hands Nadal two break points.

Right, it's on serve so far this third-round tussle.

Nadal draws Chung into the net and then looks for space down the channel, the South Korean flicks a racquet at it but can only divert it on to the blue surface.

0-30... although Chung will challenge an "out" call. It's out, just!

Jeff Tarango
Former professional tennis player on BBC Radio 5 live sports extra

Chung had the open court for a winner but he almost hit it too hard. If he had pulled out about 10% it would have been a clean winner. Nadal then had exactly the same shot Chung just had and played it perfectly.

That's better from Rafa - a rip-roaring forehand that skips beyond Chung before he can blink.

The world number two follows up with a thumping ace to hold.

It feels like Rafael Nadal is still finding his range slightly. A few wayward forehands from the Spaniard early on - he's not had much tennis this week.

Chung Hyeon does him a favour by wrapping a backhand into the tape and watching it drop agonisingly on his own side. 30-15

Good serving form from the South Korean, but he cranks a forehand wide after a fierce Rafael Nadal return. No bother, Chung slaps down an ace to hold comfortably.

Chung Hyeon wipes his goggles on his shirt, it's sweaty out there on Ashe.

The 23-year-old flops a backhand into the net to make it 15-15.

*denotes next server.

Jeff Tarango
Former professional tennis player on BBC Radio 5 live sports extra

That was incredible movement by Nadal. He was able to hit forehands from almost every part of the court. He did it four times in succession before finally hitting a backhand.

Neat work from Rafael Nadal, wrong-footing the South Korean with a disguised backhand to hold.

Commentator's curse...

Chung Hyeon engages the Spaniard in a lengthy exchange and forces Nadal to rip on into the net for 40-15.

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Rafael Nadal storms to 40-0 and has not lost a point on serve yet in this match.

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Britain's Jamie Murray and Neal Skupski, seeded 15th are through to the third round of the men's doubles following a 6-3 6-4 victory over Argentine Juan Ignacio Londero and Lithuanian Ricardas Berankis. They face Canadian Denis Shapovalov and Indian Rohan Bopanna next.

Compatriot Luke Bambridge is also through, alongside Japanese partner Ben McLachlan. They beat Croatian pair 6-3 6-7 (4-7) 6-3.

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Excellent work from Chung Hyeon, scampering across to meet a grunting Rafael Nadal forehand and making the Spaniard play by flicking it just over the tape. A slightly surprised Nadal volleys it into the gauze. A good hold from Chung.

*denotes next server.

Loose from the world number two, lumping a groundstroke way beyond the baseline.

Back to deuce, and then a skidding serve rattles Nadal's frame to give Chung the advantage.

Rafael Nadal dabs a backhand into the guts of the net as Chung Hyeon scrambles back for 30-30. The South Korean gets the Spaniard scurrying along the baseline but the pats a forehand into the tramlines. Break point Nadal.

How many towels does Rafa need? He's like a walking launderette, handing a fistful over to a ball boy at his end of the court.

Chung Hyeon gets on the board for the first time with a leaping serve down the T to make it 15-15.