Leicestershire 219 for 6 (Ackermann 66*) beat Northamptonshire 218 for 3 (Duckett 96) by four wickets
Colin Ackermann struck 66 in 31 balls as Leicestershire chased down 219 to beat Northamptonshire at Wantage Road in the opening game of the Vitality T20 Blast.
Ackermann single-handedly revived Leicestershire's chase when 112 were needed from only 42 balls, striking five fours and four sixes to see the visitors over the line with two balls to spare.
His hitting reduced Ben Duckett's T20-best 96 to a losing cause as Northants' 218 for 3 - the highest total made on the ground and the county's third-highest score in the format - proved not enough.
The required rate spiralled to 16-an-over with over a third of the innings remaining before Ackermann found his touch. He pulled and flicked Seekkuge Prasanna's final over for 19 before Mohammad Nabi swung Nathan Buck for three successive fours to leave 74 needed from 30 balls.
Ackermann's third six - off Ben Sanderson over extra-cover - raised fifty in 24 balls and his fourth - heaved over long-on, completed a quite extraordinary chase.
Ben Raine also played his part, striking two fours and two sixes in just seven balls, and Leicestershire were also helped by a six-run penalty for a slow Northants over rate which sent a final-over target of 20 tumbling to 14.
It left 14 needed from the final over and Kleinveldt sent the first ball down the leg side for five wides before Ackermann won the match in style.
It was remarkable stuff after Northants - sent in - made a huge total. Having found form with his first hundred of the season last week at Cardiff, Duckett was quickly into his work here, delicately paddle-sweeping Raine for six over long leg and lifting him over extra-cover for four. He then took 12 from Callum Parkinson's first over - with two reverse-sweeps over backward point - before another reverse-swept boundary saw Northants reach 58 at the end of the Powerplay, for the loss of Richard Levi for 6 in the third over.
A punch through extra-cover raised his seventh T20 fifty in 22 balls before a top-edged hook cleared long-leg for his second six and a perfect paddle-sweep went straight over the wicketkeeper's head for another maximum. A fierce pull took him to within sight of a century but he holed out to long-on in the final over of the innings.
Duckett shared 111 for the second wicket with Josh Cobb - the record second-wicket stand for Northants in T20s. Cobb leg-glanced Zak Chappell for his first boundary before clearing his front leg to take four more down the ground. He pulled Nabi over midwicket for his first six before smearing Cameron Delport's first two deliveries over long-on and a weaker effort that was parried over the fence for six more by Mohammad Abbas.
Having passed fifty in 28 balls with three fours and four sixes, he holed out to long-on for 56 swinging at Parkinson.
Northants' captain Alex Wakely took up the task and pulled Chappell for four through midwicket before skipping down to lift Nabi for six in the offspinner's final over. Abbas returned and Wakely steered a boundary wide of long-leg and clubbed another straight back past the bowler. A perfectly-timed pick-up shot cleared square leg and in the final over, he swung a mighty straight-drive over the Wilson Stand as he went to a 22-ball fifty in the final over.
Neil Dexter gave the chase a bright start, albeit with two boundaries via the inside edge, but having got to 38, was run out as Cameron Delport tried to take a sharp single to Prasanna at mid-on.
Two wickets then fell within the space of three balls - Delport holed out to long-on where Duckett took a good catch before Mark Cosgrove was cruelly run-out backing up as Cobb collected a firm straight drive, turned and threw down the stumps.
It appeared to be a crucial moment in the game but Ackermann's brilliance somehow got Leicestershire over the line.