The Australian world number one fires a forehand that kisses the line and flies beyond the reach of Dart's despairing dive.

Deuce.

What a sliced backhand from Barty!!

It lands then curls like a Judd Trump banana shot.

15-40.

Ace.

30-40.

Do people really get irritated by this?

Also, don't forget to add your name to texts!

Sam Smith
Former British number one on BBC TV

Given the circumstances, where she is, the occasion and who she is facing, Harriet is really keeping her head up here and keeping herself together.

I love her attitude.

Double top.

Dart has three break points!!!!

"The movement of Serena is back, and that is so important to her game," says Tracy Austin. "She is striking the ball much more cleanly too."

Williams racks up another hold off the back of some more big first serves. She has got 70% of them in, and wins 76% of the points when she does. That is not leaving much for Gorges to go at.

0-15.

Double fault.

0-30.

Does Barty have Dart-itis?

Andy Murray checks for chalk, but can't see any and his challenge is fruitless. The Croatian pair hold once more and this match remains on serve in the opening set.

The Centre Court crowd try to raise the spirits of Dart who produces a terrible second serve for her fifth double fault.

30-30.

However it seems that the comforting cheers helped the Briton who benefits from Barty's forehand swat which lands wide.

Game Dart.

Image source, Reuters

Gorges is struggling on her second serve - she has won only seven out of 21 so far - but she is not going down without a fight.

She saves four break-points here, but managing that feat for a fifth time is beyond her. A Gorges backhand loops a mile wide at full stretch, and Serena is a step closer to the fourth round.

It's not that Barty has played brilliantly it's just that Dart is not performing to the standard she produced in her previous two rounds.

30-0 before a good deep return can only be sent back long by the world number one.

Heartening for the 22-year-old.

However, Barty recovers from the blip to fire down an eighth ace.

Followed by her ninth.

Game. Her 10th.

Image source, PA Media

"Let's go!" Andy Murray does the business on serve to fend of that breaker and hold.

Good save from Herbert, but the headband sporting Frenchman then sizzles a smash long and he and Murray face another break point.

For about 10 seconds.

Game Barty.

A couple of weak serves allows Barty to move to 0-30 before the Brit makes amends with a decent one down the T.

However, another error brings up yet two more break points which Barty takes as Dart goes wide with a forehand.

Hold up!

Dart is challenging. What do you make of that computer?

"I actually think that was in".

It remains 40-15.

Herbert almost takes Skugor's head off with double-handed smash from close range. The danger of doubles... Mektic then tests out that hip of Andy Murray's with a fizzing return that leaves the Scot dipping down to his right but unable to reach it.

Spot of trouble for the home favourite. Break point Mektic/Skugor.

Gorges gets to deuce, which is an achievement in itself, but she is still yet to force a break-point in this match.

Serena smashes an ace down the T and follows her next serve in to bury a forehand winner down the line... and she holds again.

Image source, Reuters

Just getting the microscope out...nope can't see a bead of sweat on Barty.

She holds with her seventh ace.

Jonathan Jurejko
BBC Sport at Wimbledon

Pierre-Hugues Herbert needed a pick-me-up there.

Herbert struggled to land his returns in Franko Skugor's previous service game and then crashed out two double faults on his turn.

Andy Murray doesn't quite go full Gary Lineker to Paul Gascoigne at the 1990 World Cup (ask your parents...) but a few words of encouragement rally the Frenchman as the pair hold.

Image source, PA Media

Frantic stuff, speedy hold. Back to you, Andy...