Is this the turning point? Katie Boulter smashes a forehand winner into the corner. 15-30.

Calling it now, this match is going to the wire.

Katie Boulter holds to 15 to remind us that she's still very much in this.

Harriet Dart has wrestled the momentum back her way. She holds to 15 in double-quick time and suddenly leads in set three.

Harriet Dart finally breaks, at the fifth attempt!

Another error gives her an advantage which she grasps with a forehand return winner down the line.

We've almost played three hours and we're still level. What a match between these two Brits.

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But Boulter saves the break again, this time with a superb forehand down the line.

Katie Boulter can't get out of this game. She drifts a forehand wide and Harriet Dart has a fourth break point.

Another chance for Harriet Dart. A Katie Boulter mistake gives her break point number three.

But she then slices a backhand that drops an inch or so long. Deuce again.

Deuce again after Dart hits an unforced error and then Boulter smashes an overhead into the net.

Both players are feeling the pressure.

Dart is then given another break point chance after a Boulter error.

The pair play out a fine rally with Dart somehow defending Boulter smash after smash. But the world number 30 eventually finishes the point with a volleyed winner.

Deuce.

A key moment in the match and a chance for Dart to go level.

She thinks she has it with an angled forehand that has Boulter backpedalling.

But the Briton spins and smashes a forehand winner against the baseline. What a shot!

Katie Boulter opens the door by failing to put away a smash.

The game slips to 15-30 but Boulter takes the next point with a forehand winner.

Harriet Dart does still set up set point though with a passing winner after Boulter hits a sloppy drop shot.

Harriet Dart ends Katie Boulter's mini run by holding to 30. She's staying in touch, doing all she can.

Harriet Dart hasn't broken Katie Boulter since the final game of the first set. She's up against it.

Katie Boulter is charging, she's found her best form at the perfect moment.

The Briton races to 40-0, although Harriet Dart does peg her back by patiently staying in a rally before forcing an error.

But Dart then hits a forehand long to give Boulter a two-game lead.

The first break is saved as Boulter finds the net.

But the British number one manages to break at the second attempt after Dart smashes a forehand over the baseline.

Katie Boulter has gone up another level. She forces an error from Harriet Dart to bring up 0-40.

Three break points.

Katie Boulter quickly levels up the deciding set with a hold to love.

A rare easier game in what's been a properly even match so far.

And the British number two gets a big hold to start the set with two more strong first serves.

But Harriet Dart soon saves break point with a forehand winner right into the corner.

Some of the crowd are on their feet as Katie Boulter stretches to intercept a passing attempt, and manages to turn her shot into a perfect lob which sets up break point.