Southern Brave 145 for 8 (Dunkley 50, Ismail 2-19) beat Welsh Fire 144 for 5 (Bryce 44*, Adams 2-22) by 2 wickets
Southern Brave went top of the Women's Hundred table by winning a last-ball thriller against Welsh Fire in front of a record crowd of six and a half thousand for a women's game in Cardiff.
Captain Anya Shrubsole kept her nerve to get a leg bye off the final ball from Shabnim Ismail as Brave chased down the Welsh Fire total of 144-5, Brave finishing on 145-8.
Welsh Fire's Queens of Entertainment have been on the right side of some thrilling finishes, including an earlier four-run victory over the Brave, but this was a first defeat in this year's competition.
Sophia Dunkley hit a half-century for Fire, with Sarah Bryce an unbeaten 44. However, Maia Bouchier, 42, and Smriti Mandhana, 41, laid the foundation for Brave to eventually creep over the line.
Welsh Fire had to manage without one of their stars, West Indian Hayley Matthews missing with a shoulder injury, which meant Dunkley joined captain Tammy Beaumont to open the batting. Beaumont departed after a breezy start, caught on the boundary off Georgia Adams, but Dunkley was in sparkling form against her former teammates.
England allrounder Dunkley is one of the reasons Welsh Fire have flipped the table this season, going from bottom place to top after the early games. She reached her fifty off just 32 balls, getting good support in a second-wicket partnership from Scotland's Sarah Bryce.
Dunkley went first ball after reaching that half-century, bowled when trying to cut a Chloe Tryon arm ball. New batter Laura Harris upped the scoring rate, though, getting 19 off her seven balls, including a towering straight six off Lauren Bell, before being bowled by Anya Shrubsole going for another big hit.
Bryce anchored the innings with an unbeaten 44 off 36, while Adams extended her lead as the competition's top wicket-taker taking 2-22 off her 20 balls. Shrubsole, with 1 for 21 and Kalea Moore, 0 for 24, were the other most economical bowlers.
Fire's 144-5 was a competitive total, but Brave would have felt they had the firepower to chase. Ismail opened the bowling following on from her hat-trick heroics in the victory over the Pheonix, and she continued in wicket-taking form by dismissing the dangerous Danni Wyatt with her fifth ball.
Swansea-born Claire Nicholas was equally tight as Fire conceded just three runs from the first 10 balls. At one stage, two Swansea bowlers were working in tandem in Cardiff when Alex Griffiths joined the attack.
The Women's Hundred top run scorer Smriti Mandhana was soon into her stride for the Brave, with good support from Maia Bouchier. They progressed to 77 at the halfway stage, Dunkley missing a run out chance to dismiss Mandhana when she could not reach the stumps at the bowler's end.
It did not prove too expensive as the Indian lofted the ball to Ismail on the deep extra boundary off the bowling of Freya Davies, to depart for 41 off 30 balls. Bouchier took on the role as the main aggressor, though she was dropped on 35 - a tough chance for Elwiss off Dunkley running back towards long off.
Davies took a marginally easier chance shortly afterwards, also running back from mid off, this time off Elwiss's bowling as Bouchier went for 42 off 26. Elwiss made it two wickets from two balls as Freya Kemp went LBW first ball, and the pendulum swung firmly towards Welsh Fire.
Tryon survived the hat trick ball, before Adams kept her side in the game with 40, leaving the bottom order to get over the line by hook or by crook.
