Capsey, Brunt and Jones have England on the brink of a place in the semi-finals of the Commonwealth Games

A half-century to 17-year-old Alice Capsey helped England to two wins from as many matches at the Commonwealth Games as they beat South Africa by 26 runs at Edgbaston.

Capsey reached fifty in 36 balls and became just the second teenager to reach the milestone in a T20I for England after Sarah Taylor achieved the feat as an 18-year-old against New Zealand in 2007.

After Capsey's dismissal, England slumped to 94 for 5 but an unbroken 73-run stand from Katherine Brunt and Amy Jones pushed up the target for South Africa - a side they have now sunk seven times in white-ball games this summer - to 168. Despite an opening partnership of 64 between Anneke Bosch and Tazmin Brits, and an unbeaten 41 by Laura Wolvaardt, they couldn't score quickly enough against a very disciplined group of England bowlers.

Capsey had been building towards this and, in just her third international innings, she reached fifty. It wasn't the first time she had answered the call after opener Sophia Dunkley fell early.

Capsey didn't bat in her debut match, England's second T20I against South Africa in Worcester, but she got her chance when she was elevated to No. 3 in the third match of that series in Derby and smashed four consecutive fours on her way to 25 off 17. Then, having copped a nasty black eye during the warm-up for England's Commonwealth Games opener against Sri Lanka, she scored 44 at just over a run-a-ball to top score in a five-wicket victory.

On this occasion, she found herself in the action early again when Dunkley fell in the second over. Capsey and Danni Wyatt capitalised as Nadine de Klerk bowled too full and too wide, helping themselves to 21 runs off her first over including three fours in succession to Capsey.

Capsey survived two run-out chances, both times Ayabonga Khaka's shy at the stumps was off target. After Wyatt fell edging Shabnim Ismail behind to Sinalo Jafta for 27, Capsey showed she wasn't afraid of Ismail's pace, advancing steadily down the pitch to one of the fastest bowlers in the women's game and crashing her through the covers for four and, at the end of the powerplay, England were 49 for 2.

Capsey clubbed a third de Klerk full toss over cover for four as the bowler conceded 34 off her two overs and was removed from the attack. Capsey moved to 48 with an effortless six off a Bosch full toss through backward square leg and, after Nat Sciver fell edging Bosch behind, Capsey brought up her half-century with a rushed single and her acknowledgment of the crowd's applause was somewhat anticlimactic as it came only after Amy Jones was confirmed to have made her ground at the striker's end. Capsey fell a short time later, offering a simple return catch to Nonkululeko Mlaba.

Ismail showed signs of providing the impact South Africa so desperately needed in the field. She struck with her first ball of the match to remove Dunkley with the most perfect yorker which ripped out leg stump and when she had Wyatt caught behind trying to guide the ball down to third, Ismail had 2 for 2 in seven balls.

But she ended up conceding 19 runs off her last two overs as Jones and Brunt added 73 runs off 43 balls after England had lost three wickets for five runs in the space of nine balls - Sciver, Capsey and Maia Bouchier, run out in a mix-up with Jones.

With strike bowling partner Marizanne Kapp back home for family reasons, Ismail lacked the support to make enough inroads as England cruised to a respectable total, sealed with Jones' six over deep midwicket off Khaka to finish on 36 not out while Brunt was unbeaten on 38.

Bosch and Brits made a solid start, reaching 39 for 0 after the powerplay, the only concern that they were considerably short of the required run rate. Having shelled a chance at mid-on to dismiss Bosch on 4, Sophie Ecclestone finally made the breakthrough in the 10th over with an excellent delivery that spun into middle and leg stump with the batter playing all around it.

Brits also survived a dropped catch by Dunkley at backward square leg on 22 and she later overturned an lbw decision when replays showed she had got a glove on the ball attempting to reverse sweep Sarah Glenn before being struck on the pad. Brits also stayed afloat on umpire's call as England reviewed another lbw shout off Glenn, but another close call went England's way when she was stumped off Freya Kemp, failing by a fraction to ground her foot after an attempted reverse scoop as Jones whipped off the bails.

South Africa brought Wolvaardt up the order, only the second time she has batted above No. 4 in T20Is for nearly two-and-a-half years, and she managed to reach 41 not out off 33 balls. But when Brunt had the big-hitting Chloe Tryon caught by Kemp at long-on, South Africa's firepower fizzled and England eased to victory.