Kent 191 for 7 (Bell-Drummond 62, Blake 57, Harris 3-23) beat Middlesex 189 for 7 (Malan 36, Stirling 34, Denly 3-25) by three wickets
Local lad Blake clattered five sixes as the run-chase pressure reached its peak as Kent secured a sixth South Group win that maintains their qualification hopes, while consigning Middlesex to the bottom berth.
Managing director of cricket for Middlesex, Angus Fraser failed to take many positives from his sides 10th defeat of the campaign. He said: "I've just been up in the dressing room and the players are hurting. They're fed up of losing. They're not arrogant to think they can go out there expecting to win, but to keep shaking the opposition's hands and saying 'well done' is starting to get a bit thin.
"There was huge frustration today because we'd got ourselves into a reasonable position having batted well, but then we didn't have a great Powerplay with the ball - which has been a problem for us throughout the whole tournament."
Setting out in pursuit of the Middlesex total of 189 for 7 at an asking rate of 9.5 an over, Spitfires lost Joe Denly for four when his attempted pull in Tom Barber's opening over grazed the bottom edge for John Simpson to hold on to a spectacular low catch.
Kent regrouped as Heino Kuhn clubbed their first six with a back-foot force over cover that raised the home 50 after only 4.1 overs. Kuhn laced three boundaries in the next over, but James Harris had his revenge in plucking out the South African's off stump to make it 61 for 2.
Sam Billings and Daniel Bell-Drummond pushed and ran well to keep the board ticking at seven or eight an over without risk to raise their side's 100 at the mid-point of the reply.
The third-wicket pair added 42 before Billings chipped a simple catch to long-on off Patel, but Bell-Drummond went on to post his 12th short-form 50 from 29 balls and with six fours and a six.
Alex Blake upped the tempo with a six off Patel, who conceded 14 in his final over, but Harris, the former Kent loanee, returned to dismiss top-scorer Bell-Drummond for 62 as the right-hander backed away aiming to cut.
Crawley's T20 batting debut lasted four balls before he went leg before when reverse sweeping against Paul Stirling as Kent, for the first time, fell behind the Duckworth/Lewis/Stern asking rate after 17 overs.
With 40 required off 18 balls, Blake, who played his club cricket in Beckenham, unwound to take a brace of sixes and a couple of fours as Barber's over cost 22.
Sean Dickson gifted Harris a third scalp when he chipped to deep midwicket but Blake clubbed the next ball over the mid-wicket ropes to pots his 23-ball 50 and leave Kent needing nine off the last over from James Fuller.
Blake opened the face to clear the ropes over point to reduce the target to three, but was caught at deep mid-wicket next ball up to go for 57 from 27 balls, leaving Haggett to glance the next ball for a victorious boundary.
Bowling first after winning the toss in light drizzle, Kent made a sloppy start offering too much width in the opening overs allowing Paul Stirling to crash a trio of fours in Denly's opening over, while Dawid Malan collected four and the game's first six off the third from Mitch Claydon.
Malan, available and with a point to prove following his exclusion from England's Test squad, cleared the ropes in the next overs from Adam Milne and Calum Haggett as Middlesex raised their 50 from only 27 balls.
By the end of the powerplay Spitfires had leaked 10 fours and three sixes enabling Middlesex to canter to 71 without loss during the Powerplay.
The hosts made their first breakthrough after 6.1 overs when Malan chipped a meek return catch to Denly to depart for 36 off only 19 balls then, Imran Qayyum struck in his first over, having Stirling caught at backward point off a mis-timed slash to make it 76 for two.
Bell-Drummond's second delivery in T20 cricket was dispatched over the long-on ropes for six by John Simpson as Middlesex raised their 100 in the 10th over.
Qayyum returned to have Eoin Morgan caught off a skier at long on then Simpson departed for 29 in near identical fashion against Denly, who rattled James Fuller's stumps four balls later to finish with three for 25.
Qayyum's figures were ruined when James Franklin clubbed three sixes in his final over as he and Stevie Eskinazi added 49 for the sixth wicket before Franklin and George Scott departed in Claydon's final over of the innings.