A second match point for Zverev.

Norrie on serve and he's wide with his first. A slower second is good and now it becomes a battle of wills.

Zverev steps forward to meet a rising ball just in front of the baseline but it's swiped into the net.

Wang Xinyu saves that break point and turns the game on its head, holding her nerve to touch a Dart return over at the net.

We're going to a deciding set on court two.

Tim Henman
Former British number one on BBC TV

Where does Norrie go now? See ball, hit ball. He didn’t have too much time to think.

Zverev's trusty serve denies Norrie the chance to get over the line and we're level again.

And the momentum shifts in Norrie's favour with Zverev firing into the net.

Set point for Norrie.

Image source, Getty Images

Wang Xinyu starts her service game with a double fault. Nerves?

She squanders two set points, errors allowing Harriet Dart back into the game at deuce, and as she sends a soft forehand into the net, Dart has break back point.

Fine work in a big pressure moment from Norrie as he whips it down the line to draw level.

Charlotte Coates
BBC Sport at Wimbledon

Huge cheers around Court One as Ben Shelton reaches the last 16 at Wimbledon.

He holds up an outstretched hand to show the number five after playing 15 sets in three matches.

The marathon man does it again.

It turns so quickly, though, as Zverev gets a break of his own and then forces two errors from Norrie on serve to get to match point.

Norrie is serving to stay in it.

Oooof. That serve had plenty on it at 135mph from Zverev. The chalk skips up off the line and Norrie can only return long. 4-3.

A bit of help from the net cord, nudging Zverev's forehand wide, gives Norrie a 5-3 lead.

Johanna Konta
Former British number one on BBC TV

Wang Xinyu has been quite adaptable at the net and she seems to read the ball reasonably well up there.

She needed to make that return and she got the ball in play.

Harriet Dart was very close to having a match point. She knows how to lean into her return games and maybe Wang might start to feel a bit nervous.

John McEnroe
Three-time Wimbledon singles champion on BBC TV

Norrie has kept relentlessly positive – despite the score line.

Zverev makes up for it on his next serve but that early break is looking so crucial now for Norrie as the Brit goes on to hold twice, opening up a 4-1 lead.

A big chance for Wang Xinyu at a crucial moment as she finds herself with a break point.

And she gets it! Harriet Dart can't return over the net and Wang will now serve for the second set.

Norrie hasn't fared too well in tie-breaks this year - he's won six and lost 15.

Let's see how he gets on here.

An early break to take a 2-0 lead after Zverev double faults.

Zverev doesn't need to employ any new tactics on his serve.

The German goes on to hold to love. It's just too easy.

We're heading for a tie-break.

Tim Henman
Former British number one on BBC TV

Within areas of the sport, people think that’s disrespectful. I think it’s a mad tactic, because players do stand a long way back to return serve.

Wang Xinyu races through the start of her service game to 40-15 but Harriet Dart finds her way back into proceedings.

Levelling at deuce, the Brit plays aggressively but misses an overhead smash at the net to give her opponent advantage. From there, Wang gets the hold with a helping hand from the net cord.

What a rally. Zverev, stood almost on top of the net, has to reach way back to hook a return off the grass, Norrie volleys back at him and the German can only hit the net.

Wow. That's confidence from Norrie to get the game over the line with a 40-15 lead, he pulls off an audacious underarm serve and Zverev is caught by surprise.

Almost too aggressive from Wang Xinyu as, for the third time in the game, she puts too much on a forehand attacking a second serve.

Harriet Dart won't mind one bit. The ball sails long and the British number two secures another important hold.