Alex Hartley
Former England bowler on BBC Two

South Africa have to prove themselves before the Commonwealth Games. They have to get early wickets. They've struggled with putting England under pressure in key stages of play.

Image source, BBC Weather

The forecast looks pretty good for Derby - a chance of the odd shower but hopefully nothing which will impact upon the game too seriously.

A toss of the coin by England stand-in skipper Nat Sciver and South Africa counterpart Chloe Tryon, who stands in for Sune Luus, calls incorrectly.

Sciver has decided to make first use of the pitch with the sun shining at the County Ground.

Image source, Getty Images

England will again be without captain Heather Knight this evening.

The 31-year-old has irritation in her hip joint. She has had an injection and England's medical staff will continue to monitor and treat her ahead of the Commonwealth Games.

Nat Sciver will skipper England again in her absence.

Image source, Getty Images

England's women have absolutely dominated their five white-ball matches against South Africa so far this summer.

Victories by five wickets, 114 runs and 109 runs in the one-dayers have been followed by back-to-back wins by six wickets in the first two Twenty20s.

Ordinarily, this evening's final T20 might carry the feel of a meaningless dead rubber. But with the Commonwealth Games just around the corner it's an opportunity to maintain a winning streak, and keep confidence levels up.

We'll have all the key moments from the County Ground in Derby during our live text commentary so stick with us for the next few hours.