Svitolina goes 40-30 ahead before Barty forces deuce.. then, all of a sudden we have a set point to the Aussie...

Right then, Svitolina serves to stay in the set. She could have been serving for the set. But she makes a nervy start and trails 0-30. Chance.

Oh Ash! Looking at a second serve for a 0-40 lead, Barty dumps a forehand return into the base of the net. She'll be furious.

Svitolina turns up the volume on the impact screeching, which works as Barty slices a backhand into touch for 30-30...

Deuce comes and goes, then returns for a fourth time, Barty eventually getting her nose back in front by approaching the net and putting away a volley.

The Aussie sits back on her chair, using her towel to wipe the sweat she's just accumulated in that tricky game from her face and shoulders.

Ah-ha! Thirty two minutes into the match and we have our first break point. That's in favour of the Ukrainian, who can't convert as Barty rallies...

A net cord puts Barty 30-15 ahead before a double fault from Aussie leaves coach Craig Tizer shaking his head. And cursing.

Svitolina goes to the technology for another Hawk-eye challenge, her third of the match, and the third she gets wrong. Don't ask her to pick your football accumulator.

Side to side, forward and back, Barty is trying to get Svitolina moving. The Ukrainian is a bundle of energy, spring forward to reach a drop-shot but can't get it over the net. That's 30-30... and a chance?

Svitolina's second serve is punishable.. but Barty can't make her pay as a forehand flies long. Off the hook.

Barty continues to cruise along with the ball in hand, moving 40-0 ahead. Not a break point in sight. Hang on... Svitolina battles back to 40-30.. is this the time? Nope, Barty plays a stunner of a point, moving forward and nailing a backhand pick-up.

Quality off the scale so far.

Both players have a service point winning percentage in the 80s, Svitolina looking to improve her tally further as she goes 40-0 with a string-busting backhand winner.

The Ukrainian mixes it up in the next point with a drop-shot but Barty scampers after the ball and, not only gets there, knocks over a cross-court winner.

Another long joust ends in Svitolina sealing the hold.

Svitolina sits in her chair and mutters something to herself at the changeover. It's wasn't a lyric to her favourite Rihanna song. She's well in the zone.

Ash Barty know a thing about fast deliveries being a former cricketer and the power she gets from her serves is mighty impressive for someone standing at 5ft 6in.

More strong arm stuff from the Aussie leaves even Svitolina struggling to get the ball back.

A garish orange-coloured Porsche sits in the corner of the Shenzhen stadium. Not sure if the winner will be driving that home...

Svitolina's serves have been going from 0-60 quicker than any supercar this week, but Barty starts to read them better in the Ukrainian's second service game and pushes her to 40-30 before Svitolina does land a first serve which Barty can't return cleanly.

Imagine if you said this would be happening today to the Original Nine back in 1970...

Like Elina Svitolina, the recently-retired Aggie Radwanska knows a thing or two about winning the season-ending shindig.

Barty is aiming to get that feeling for the first time today on her first appearance. Another high-quality service game from the Aussie keeps the score as expected.

Svitolina, rather unbelievably, has hit more aces than her opponent this week. The Ukrainian has whacked down 33 in nine sets... can she find a way past Barty? The answer is yes on the evidence of this opening hold. Svitolina nails an ace down the T to hold to love. Impressive.

Strong start for Ash Barty, not allowing Svitolina a sniff as she holds to 15. A backhand slice from the baseline hits the net and the Aussie gets her side of the board ticking.

Ashleigh Barty points to the ball kid, she grabs a ball and will open the serving...

If history proves to be correct then Elina Svitolina will be lifting the title. The Ukrainian has won all five of their previous meetings, dropping just two sets.

But they have only played once this year - Barty's breakout season which will end with the world ranking and a French Open title - and it was their closest match yet as Svitolina won 7-6 (10-8) 5-7 6-4 at Indian Wells.

"It took a few days to get over," Barty said. "I felt like in that match, over the course of the three sets, I did a better job of playing the way that I wanted to play. It was just missed opportunities.

"The bonus is I get another chance to try to rectify that as best that I can.

"Elina has the ability to put balls in very awkward situations, make you play a lot of balls, make you earn every single point. I'm looking forward to that challenge. Knowing it's the last one of the year, you can leave no stone unturned."

So where's your money going? Don't worry, you don't have put £4m on it. Let us know using #bbctennis

Hello! It's not all been plain sailing for the WTA Finals in its new home of Shenzhen (more of that later...) but this is pretty much the final which many would have picked to see in the showpiece.

The world number one against the defending champion.

The big-serving slicer and dicer against a baseline waller.