Fi Morris comes into the attack and Fran Wilson puts her opening delivery away for four, emulating the fine foot movement by Heather Knight at the end of the previous over.

Morris gets away with a long-hop as Wilson's switch-hit is straight at the fielder before an orthodox square cut brings her a single.

By comparison, the Vipers were 99-1 after 10 overs with Danni Wyatt going strong on 60 not out.

Fran Wilson sweeps Amanda Wellington fine for four as the leg-spinner, for once, gets her line all wrong.

The Vipers are looking sharp in the field but they can do nothing as Heather Knight uses her feet superbly before driving the final delivery of the over through the covers for another boundary.

Storm need 101 more from 11.

Lauren Bell continues, striving for greater control than she achieved in her two previous overs.

A no-ball gives Heather Knight a free hit but she doesn't quite make clean contact, allowing Fi Morris to make the save on the boundary and keep her to one.

No such luck next ball, though, as Fran Wilson whips it away between mid-wicket and mid-on for four.

Despite that, the rate has now climbed to 9.25 an over.

It's been a good first over by Amanda Wellington, but it ends with Heather Knight sweeping for four. Knight is the key now for Western Storm. Fran Wilson is now batting at the other end.

Kate Cross
England seam bowler on BBC 5 Live Sports Extra

That's a great bit of work from Carla Rudd there.

That's a lack of awareness from Rachel Priest, she was looking for a run down the crease.

A full toss by Lauren Bell is a gift for Rachel Priest who belts it away through mid-wicket for four.

Priest then flicks towards long leg but is denied another four by a sprawling Tash Farrant - the single, though, brings up Western Storm's 50.

Image source, Rex Features

Danni Wyatt is next into the fray for Southern Vipers.

Heather Knight moves to the off to give herself room and sweeps her England team-mate behind square for four and a single makes her to first player to 1000 runs in all Super League matches.

Wyatt is too short with the final ball of the over and Rachel Priest helps it into a big gap on the leg-side for another boundary.

The first Southern Vipers bowling change brings Suzie Bates into the attack. Kiwi to Kiwi with Rachel Priest on strike.

Nothing doing from the first two deliveries, but Priest then smashes the next one down the ground for four.

Storm are keeping the required rate under nine an over - near enough exactly what was required at the start of their innings.

Tash Farrant comes in again and is immediately smeared in front of square for four by Rachel Priest. That's the sort of shot we saw from the New Zealander in her 72 in the 2017 final.

A fuller length restricts the Storm batters to singles before Heather Knight clips her away for two to end the over.

After a boundary by Heather Knight, a loud lbw appeal from Lauren Bell follows, but that one is just missing leg stump.

The youngster gives the Storm skipper too much width with the next delivery and it is flashes away through backward point for another four.

Two successive wides follow before Rachel Priest ends the over with a single.

Western Storm skipper Heather Knight finds herself in the middle in the opening over.

She avoids any repeat of Smriti Mandhana's impetuosity as she blocks out the last three deliveries.

Just one from the bat and a wide in Tash Farrant's opening over. Lauren Bell will open from the other end.

Kate Cross
England seam bowler on BBC 5 Live Sports Extra

That was a strange bit of cricket.

Smriti Mandhana's shot looked like going over mid off.

Marie Kelly didn't pick it up until she dived for it, but it's a great catch in the end.

Rachel Priest - match-winner in 2017 - and Smriti Mandhana are at the crease for Western Storm and Tash Farrant has the ball. To score 173 in 20 overs, Storm need a rate of 8.65 per over.

So, just one innings to go before the Women's Super League is consigned to cricket history.

To win, Western Storm are going to have to make the highest second-innings total in a final in the four years of the competition.

But they have plenty of batting, led by Rachel Priest, Smriti Mandhana and England skipper Heather Knight.

A quick statty bit about Danni Wyatt - she made 466 runs for Southern Vipers in this year's competition at an average of 42.36, with a strike-rate of 166.42.

How important might the wicket of Danni Wyatt prove to be for Western Storm?

The England all-rounder looked destined for a century - which would surely have given Southern Vipers one hand on the trophy - but as it is, we're set for an enthralling run-chase.

Carla Rudd finds the boundary with her one and only ball - a great impact!

Southern Vipers make a very impressive 172-7 - equalling the highest score Western Storm have ever conceded.

But you feel it could've been 15-20 more after the way Danni Wyatt was going.