Thunder 176 for 9 (Smale 58, Lamb 44, Gordon 3-23, Higham 3-28) beat The Blaze 174 (Gaur 3-33, Jones 3-37) by one wicket
Bolstered by the return of four England players, Thunder proved too strong for The Blaze as the Trent Bridge side slipped to a fourth defeat in five matches in the Rachael Heyhoe Flint Trophy - but only just, scraping home to a nervous one-wicket victory in a gripping finish.
England A batter Seren Smale made 58 and England opener Emma Lamb 44 and at 89 without loss in 15 overs, Thunder looked to be cruising to a second win of their campaign. Yet they collapsed to 161 for 9 after skipper and left-arm spinner Kirstie Gordon and off-spinner Lucy Higham took three wickets apiece and England leg-spinner Sarah Glenn 2 for 33 in a gutsy fightback.
It was left to last-wicket pair Phoebe Graham and Hannah Jones to hold their nerve and see their side over the line, Jones hitting the winning boundary in the 45th over.
England's 18-year-old left-arm seamer Mahika Gaur had taken 3 for 33 and left-arm spinner Jones 3 for 37 as The Blaze were bowled out for 174 in 46.4 overs.
Gordon made 43 - her highest score since an unbeaten 60 for Scotland Women nine years ago - as the East Midlands regional side recovered from 108 for 7, but her efforts in the end were in vain.
After Thunder had won the toss, England opener Tammy Beaumont (25), back in Blaze colours for the first time this season, helped the home side to enjoy a productive powerplay, reaching 49 for 2 from 10 overs, yet the Blaze innings lacked the early partnerships that might have given it real impetus.
Teresa Graves picked up a couple of early fours but nothing more before she was bowled middle stump by a superb ball from Gaur, who then produced a near-identical delivery, full and swinging back in, to dismiss South African international Nadine de Klerk for 3.
Beaumont, dropped on 24 off Graham, added only a single before becoming the third victim of Gaur's impressive opening spell, reaching for her shot and chipping to the left-armer's mid-on, where Kate Cross made no mistake.
Blaze had been scoring at five an over but Ellie Threlkeld's introduction of left-arm spin at both ends applied the brake and brought two wickets in quick succession as Marie Kelly, looking nicely set on 23, miscued Jones to midwicket and Glenn gave her fellow England spinner Sophie Ecclestone a straightforward caught-and-bowled.
Beth Gammon and Gordon rebuilt to a degree but Gammon was bowled making room against Jones and when off-spinner Fi Morris took over at the Radcliffe Road end, her first ball accounted for Ella Claridge, who hit straight to cover.
Gordon and Sophie Munro put on 35 only for a breakdown in communication to see the latter was run out. Gordon and Higham added value with a further 29 in 28 deliveries before the latter was bowled by Jones.
The Blaze have been more effective with ball than bat so far but their hopes of denying Thunder looked to be disappearing in the first five overs of the reply, when new-ball pair De Klerk and Grace Ballinger struggled with their lines and conceded nine boundaries as Lamb and Smale helped themselves to runs.
Even after a double bowling change, Thunder pushed on to 69 without loss after 10 overs, well ahead in the game. But from 89 for none in the 16th over, they suffered a collapse that saw six wickets fall for 39 as the Blaze spinners fought back.
Glenn's introduction brought a double breakthrough as Lamb's slog-sweep lobbed to mid-on and Katie Mack was bowled for just a single, before Higham's off-spin claimed two more wickets. Higham had Morris caught at mid-on and Threlkeld at mid-off.
Smale completed her half-century from 57 balls but Thunder had lost four wickets for 21 runs.
Naomi Dattani was trapped leg before on the back foot as Higham struck for a third time, after which Blaze suddenly sensed an unlikely win as Gordon returned at the Stuart Broad End to bowl Smale with Thunder's target still 47 runs away.
Ecclestone and Cross eased Thunder's nerves a little by bringing the required runs below 30 but then Gordon took two wickets in two balls, bowling Ecclestone and then pinning Gaur in front to leave the visitors in peril at 146 for 8.
As all three Blaze spinners completed their 10 overs the balance seemed to tip towards the experience of Cross to get the job done. Munro raised the pressure again as she uprooted the England bowler's middle stump with one that kept low, but with overs on their side, Graham and Jones kept calm to see their side home.