Ned Eckersley smashed 50 as Durham earned an extraordinary two-wicket win over Leicestershire in an increasingly tetchy T20 Blast North Group game.
Chasing 169 for victory, Durham were reduced to 108-8 at New Road.
But Eckersley and Liam Trevaskis (30) scored 24 runs off a controversial 19th over from Naveen-ul-Haq for victory.
Elsewhere, Brett D’Oliveira hit 61 as unbeaten Worcestershire ended Lancashire’s 100% start with a crushing eight-wicket win that takes them top.
Eckersley delivers for Durham
Worcestershire’s win was serene, but the day’s real drama came as Eckersley steered Durham to a dramatic victory over his former side that saw tempers flare after the game’s conclusion.
Eckersley scored 50 from 36 balls in a 62-run partnership with Trevaskis as the Foxes attack struggled under the pressure.
Afghanistan fast bowler Naveen bowled two beamers in the penultimate over and had to be taken off as the visitors completed an unlikely win that ensured a third defeat in three for their hosts.
Foxes opener Scott Steel had seemed to lay the foundations with five fours and two sixes in a 38-ball 53 and was ably supported by Arron Lilley (31) as the hosts made 168-9.
Durham lost five wickets for 20 runs in 3.5 overs as they slumped from 65-3, with Lilley taking 3-26, before Eckersley and Trevaskis intervened.
The victory takes Durham up to second, behind Worcestershire.
D’Oliveira excels as Rapids romp home
D’Oliveira had a much more relaxing afternoon in the summer sun, as Worcestershire recorded a second win in three unbeaten matches so far.
D’Oliveira and Riki Wessels (40) put on 79 for the first wicket and the Rapids were always on top as they easily chased down a below-par 132-4.
By the time Wessels was bowled by Matt Parkinson the damage had been done, and D’Oliveira reached 50 off 36 balls before steering his side home without alarm.
D’Oliveira also impressed with the ball, taking the wicket of Liam Livingstone (25) as he bowled two miserly overs for just five runs.
Only England wicket-keeper Jos Buttler, who hit 55 off 46 balls, showed any sort of sustained intent for Lancashire but the total always seemed too low.
Clarke bludgeons Outlaws to victory
Opener Joe Clarke bludgeoned 136 off 65 balls – including 11 sixes – as Notts Outlaws defended a total of 214-7 to beat Northamptonshire Steelbacks by 14 runs at Wantage Road.
Only Peter Trego (24) joined Clarke in passing 20, but the latter’s one-man show – which included proved enough despite a spirited chase by the hosts.
Northants were always struggling to keep in touch with the daunting total, despite the best efforts of Josh Cobb (62) and Rob Keogh (45).
The home side’s hopes all but ended when Cobb’s 32-ball innings was ended by Luke Fletcher (2-41), while Jake Ball finished with 3-58 as Notts closed out a first T20 Blast win this season.
Dan Mousley top-scored with 56 off 40 balls to ensure victory for Birmingham Bears over Derbyshire Falcons.
Fynn Hudson-Prentice hit 41 off just 22 balls before being run out as Falcons reached 160-8.
But despite being in deep trouble at 18-3, Bears recovered impressively and Sam Hain (25) and Michael Burgess (22) provided valuable back-up for Mousley.
Half-centuries by Nick Selman and Australia batsmen Marnus Labuschagne saw Glamorgan ease past Essex in the South Group.
Will Buttleman (36) and Michael Pepper (29) were the only Essex batsmen to get past 25.
Leaning stars as Spitfires soar
Jack Leaning’s unbeaten 81 proved the difference as his fearless hitting helped Kent move top of South Group thanks to a thrilling five-run win over Gloucestershire at Canterbury.
Leaning came in with the Spitfires struggling on 16-3 after three overs and shared a vital 76-run stand with skipper Daniel Bell-Drummond (51).
Leaning took centre stage, hitting six fours and four sixes in his 51-ball knock as the hosts reached 183-5 from their 20 overs – a total greatly boosted by Leaning and veteran all-rounder Darren Stevens smashing Josh Shaw for 27 runs off the last six balls.
Chris Dent (40) and Glenn Phillips (38) made rapid contributions in the Gloucestershire reply as they steadily upped the tempo to need 10 for victory off the final over.
But Frederick Klaassen’s stunning inswinging yorker with the first ball removed Benny Howell (44).
Matt Taylor went the very next delivery and, with Graeme van Buuren also run out, Kent were able to claim a third win from three this season.