Halep reaches the backhand and cuts it back into play. Muguruza drops it just over the net and Halep can't quite play the pass.

Muguruza takes the opening set!

Unbelievable rally - 20 shots!! Both players smashing the ball to and fro before Muguruza crashes a forehand which Halep can only return wide.

The Spaniard then brings up another set point.

Double fault! Wow.

Her first of the match. Another set point for Halep.

Huge serve out wide. Level again.

Muguruza doesn't handle the deep baseline strokes from Halep and there's a third set point for the fourth seed.

Brilliant reach from Halep, who cuts a forehand back into play from a tight angle. She then squeezes a stunning forehand down the line!

Incredible.

Good defence from Halep as Muguruza's forehand loops over the baseline.

One more set point.

Here they come.

Good angle from Muguruza and Halep won't reach it fully. The Romanian then pops a forehand up and way over the line.

She stares frustratingly at the baseline.

Muguruza looks tired as she drags a backhand wide. She's having to work hard on each point.

Another backhand slumps into the net.

A big serve down the T. Clean hitting forces Muguruza into the net.

Better from Halep.

Muguruza defends the point well then thumps a backhand down the line. Halep's return then flies long.

Halep skews the backhand.

Muguruza gets an early mini-break.

More good net play from Muguruza to take the advantage and she saves the set with a big serve out wide.

Excellent stuff! We're off to a tie-break.

Halep is chasing and chasing as Muguruza smashes a forehand into the corner. She puts away the two volleys too and we're at deuce.

Muguruza is getting a bit frustrated. She drags a backhand short... then long. 23 unforced errors.

An ace. That will help. Halep then reaches for a forehand and clips the line. Two set points.

Momemtum has just shifted a little. Halep wins her 10th point in a row before a first double fault brings Muguruza on the board.

Muguruza then hooks a forehand wide. She shakes her head. The Spaniard plants another one into the net.

Oh no! Muguruza gets it all wrong. Halep's stretched pick-up clips the net and Muguruza gets caught in two minds.

She ends up placing it into the cords, with the entire court open. We're level again.

Superb from Halep, who keeps thumping deep baseline strokes back at Muguruza and eventually the Spaniard nets it.

Three break points.

It kicks up for Muguruza to hit down the line in the rally but she scuffs it. She then plants a forehand into the net...

30-0 to Halep.