Capseys fifty was her fifth in The Hundred
The Hundred womens competition, Edgbaston
Oval Invincibles 174-5 (100 balls): Capsey 52 (29); Baker 2-24
Birmingham Phoenix 152-6 (100 balls): Lister 33* (18); Wellington 2-27
Oval Invincibles won by 22 runs
Alice Capsey found her best form as Oval Invincibles beat Birmingham Phoenix by 22 runs to earn their first victory of this years womens Hundred.
The 21-year-old all-rounder, four years on from making her professional debut aged 16 in this competition, struck 52 from only 29 balls as the Invincibles piled up 174-5 - their highest total in the womens Hundred and the third highest by any team.
Capsey has struggled for form in the past year but built on the platform laid by Lauren Winfield-Hill and Meg Lanning, who took 54 from the powerplay - also a womens Hundred record.
After Lanning fell for 36 and Winfield-Hill for 33, the right-handed Capsey, with only one fifty in her past 32 T20 or Hundred innings, hit eight fours and one pulled six.
Strong on the drive and with her inventive reverse sweeps, she put on 57 in just 29 balls with Paige Scholfield, who made 25 not out from 16.
Requiring the highest successful chase in the womens Hundred, Phoenix never really threatened in pursuit despite 22 from Georgia Voll, 25 from Emma Lamb, 29 from captain Ellyse Perry and Scotland international Ailsa Listers impressive 31 not out.
Perry hit Australia team-mate Amanda-Jade Wellington for six but was caught behind off the leg-spinner a ball later. Wellington also ran out England international Lamb at the non-strikers end with a clever flick on to the stumps as Phoenix ended on 152-6.
The win means Invincibles, champions in the first two years of the Hundred, join Phoenix on four points after three games, each having one win and two defeats.
Capsey is a product of The Hundred, having made her name by scoring fifty in her second game at Lords in 2021.
Back on this stage, she looked more confident and destructive than she has throughout her recent struggles.
Capsey scored 79 and 57 for Surrey in the domestic 50-over competition last month but has five single-figure scores in her six T20 innings for England this year. She was left out of Englands one-day international series defeat by India entirely.
But, back to close to her best, the highlight of this innings was a reverse sweep lifted over backward point.
Two balls earlier she offered a chance with the same shot on 21 but the power took the ball through the hands of Sterre Kalis.
"For me it is such a go-to shot and something I lost a bit of confidence in for a while," Capsey told BBC Two. "To have that confidence to stick at it, it was nice a few came off today.
"From the get-go I felt all of my options were on."
There are four games on Wednesday - two mens and two womens.
Southern Brave host Northern Superchargers with the womens match starting at 11:30 BST and the mens 15:00.
Welsh Fire also host Manchester Originals in the womens competition from 15:00 with the men following from 18:30.
You can follow ball-by-ball commentary on BBC Radio 5 Sports Extra, BBC Sounds and the BBC Sport website and app.