Live Commentary: Caroline Wozniacki vs. Duan Ying-Ying - as it happened

Good evening! The players have just finished their warm-ups and we're ready to go on the main showcourt - Arthur Ashe.

Duan opens with a double-fault but then shows off a classy backhand to bring it back to 30-30.

BREAK! Immediate advantage for Wozniacki as she takes her first break point at 30-40.

Again Wozniacki comes through the game after being pegged back to 30-30. Sitting in the crowd is boyfriend and two-time Major golf winner Rory McIlroy of Northern Ireland.

Very odd moment as the umpire says that Duan didn't get to Wozniacki's short forehand before the second bounce. Wozniacki plays on anyway and gets flummoxed by the bounce of Duan's arcing shot but manages, with the tip of her frame, to get the ball over. Duan tries to argue that the ball was up but apparently she can barely speak English!

Duan gets on the board by holding to 30. She's got a sizeable frame and is using her power to force Wozniacki on the defensive.

After a nervy start, Duan is now taking the game to Wozniacki with her deep, powerful groundstrokes. She has a break-back point but can't take it as Wozza delivers a classic one-two, serve-forehand punch.

Duan fails with a second break-back point before Wozniacki comes through to hold with an ACE down the middle.

Wozniacki is one of the best defensive players in the women's game and she's just shown why there with some tireless running before Duan hit long.

DOUBLE BREAK! Not so good from Duan there as she is broken to 15 by Wozniacki with numerous errors.

Wozniacki has made 2 unforced errors, Duan 13!

ONE BREAK BACK! Well this is a bit weird, isn't it? Duan now gets one break back, to love, thanks to some more mighty forehands.

DOUBLE BREAK! Wozniacki restores her double-break advantage as Duan double faults for the second time at 15-40.

SET! The Dane comes through the opener in 35 minutes. Duan was looking to get a break back at 0-30 but made more unforced error to make it easy for Wozza to take the set.

A solid start to the second set from the Chinese. She was made to hit so many balls in the final rally but held firm before beating Wozniacki with an in-to-out forehand.

Duan confidently approaches the net and puts away a high backhand volley to make it 30-30 before denying Wozniacki the game with another no-holes barred backhand.

BREAK! Another wallop off the backhand wing down the line sees Duan move ahead an early break in the second.

Chance for Wozniacki to break back straight away as Duan shoots long with a forehand...

Well saved by the Chinese as she backs up her first serve with a swiped forehand to the corner.

Some start to the second set for Duan. She consolidates the break thanks to some mighty hitting off both wings.

Wozza gets on the board in the second set by holding to 30. Can she now level it up by breaking her lanky opponent.

Wozza's looking menacing at 15-30 but can't do anything to stop Duan's booming forehand as the Chinese brings it back 30-30. The Dane does now have a break-back point though as Duan nets...

Saved! Great stuff from the underdog as she steps into a backhand and blasts it cross-court for a winner.

BREAK BACK! Wozniacki converts at the third time of asking and we're back on level terms in the second set.

BREAK RESTORED! Duan wastes no time in regaining her advantage in the second as Wozza hits long at 15-40.

Duan slaps her 15th winner of the set (!) to save the second of two Wozniacki break-back points.

Another winner prevents Wozniacki breaking on the third opportunity before the unheralded Chinese comes through to move within a game of the second set.

Wozniacki forces Duan to serve out the set by holding to 15. Big moment coming up for the Grand Slam debutant.

Dogged play from Wozniacki as she prevents Duan setting up two set points. 30-30.

Break-back point Wozza...

BREAK BACK! And she takes it as Duan's forehand wildly flashes wide. The Dane now needs to hold serve to even the second.

Brutish start to the game from Duan as she batters the Dane's backhand. 0-15.

And then Wozniacki DOUBLE FAULTS. Dear oh dear.

The next two points are freebies for Wozniacki as Duan hits long with two forehand returns.

A big ACE down the middle opens up game point but she can't take it as she frames into the stand. It's not SET POINT DUAN...

She can't take it as Wozniacki's backhand is brilliantly deep.

"Come on!" Wozniacki says to herself as she comes through a tough game for her third in a row that levels up the set at five games apiece.

BREAK! That's four games in a row for Wozniacki as Duan hits long. She'll now serve for the match and a place in round two at Flushing Meadows.

Duan has two break-back points to take us into a tie-break...

Both saved by Wozniacki! Impressive resolve from the Dane as she hits a rare winner.

Wozniacki then misses an easy forehand to gift the Chinese another break point but she can't take it as she shoots long with a backhand.

Wozza has her first match point...

That was a really tough examination of the sixth seed. She'll now face either Chanelle Scheepers Chanel Simmonds, both from South Africa.

Fair play to Duan. This was her first Grand Slam and she showed that she certainly packs a punch.

Thanks for joining SM this evening. Next up on Arthur Ashe is a certain Roger Federer, five-time winner at Flushing Meadows. Our coverage of that one will be live on site very soon. Look out!