Bolstered by the return of four England players, Thunder proved too strong for The Blaze as the Trent Bridge outfit suffered a fourth defeat in five Rachael Heyhoe Flint Trophy matches - but only just as they eked out a nervy one-wicket win in a thrilling finish.
England A opener Seren Smale made 58 and England opener Emma Lamb 44, and at 89 not out from 15 overs, Thunder looked set for a second win of the campaign. But 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 took 2 for 33 in a valiant fightback.
It was left to the final wicket pair of Phoebe Graham and Hannah Jones to hold their nerve and see their side over the line, with Jones hitting the winning boundary in the 45th over.
England's 18-year-old left-arm seamer Mahika Gaur took 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 were ultimately in vain.
After Thunder won the toss, England opener Tammy Beaumont (25), back in Blaze colours for the first time this season, helped the home side enjoy a productive powerplay to reach 49 for 2 from 10 overs, but the Blaze innings lacked the early partnerships that could have given it real momentum.
Teresa Graves picked up a couple of early fours but nothing more before she was bowled on middle stump by a superb delivery from Gaur, who then produced an almost identical delivery, full and swinging back in, to dismiss South African international Nadine de Klerk for 3.
Beaumont, dropped by Graham on 24, added just 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 scored at five an over, but Ellie Threlkeld's introduction of left-arm spin at both ends put the brakes on and brought back two wickets in quick succession as Marie Kelly, looking comfortable on 23, miscued Jones to midwicket and Glenn had her fellow England spinner Sophie Ecclestone caught and bowled.
Beth Gammon and Gordon rebuilt to some extent, but Gammon was bowled off Jones and when off-spinner Fi Morris took over at the Radcliffe Road end, her first ball was to Ella Claridge, who hit straight to cover.
Gordon and Sophie Munro put on 35 before a breakdown in communication saw the latter run out. Gordon and Higham added another 29 off 28 deliveries before the latter was bowled by Jones.
The Blaze had been more effective with the ball than the bat, but their hopes of chasing down Thunder seemed to disappear 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 were well in the game with 69 not out from 10 overs. 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 whammy with Lamb's slog-sweep lobbing to mid-on and Katie Mack trapped for a single before Higham's off-spin claimed two further wickets. Higham trapped Morris at midwicket and Threlkeld at deep midwicket.
Smale reached her half-century off 57 balls but Thunder had lost four wickets for 21 runs.
Naomi Dattani was trapped leg before as Higham struck for the third time and Blaze suddenly sensed an unlikely victory when Gordon returned at Stuart Broad End to bowl Smale with Thunder's target still 47 runs away.
Ecclestone and Cross calmed Thunder's nerves a little by reducing the required runs to under 30, but then Gordon took two wickets in two balls, bowling Ecclestone and then trapping Gaur to leave the visitors in peril at 146 for 8.
With all three Blaze spinners bowling their 10 overs, the balance seemed to tip in favour of the experienced Cross to get the job done. Munro piled on the pressure when she uprooted the England bowler's middle stump with a low delivery, but with the overs on their side, Graham and Jones remained calm to see their side home.