Northamptonshire ended Glamorgan's 100 per cent record in the Friends Life t20 with a dramatic seven-wicket win in Northampton.
Glamorgan scored 153-7 from their 20 overs with Murray Goodwin top-scoring with 47 off 31 balls as Mohammad Azharullah posted his best Twenty20 figures of 4-14.
The Steelbacks then clinched victory off the final ball of the match thanks to Cameron White hammering 68 off 52 balls and skipper Alex Wakely smashing an unbeaten 52 off 39 deliveries.
Glamorgan still lead the Midlands/Wales/West Division with eight points from five games, but Northants are now only two points behind with six points from four matches.
Wakely won the toss and chose to field, but Glamorgan captain Jim Allenby got his side off to a decent start by hitting 36 from 26 balls in an opening stand of 57 with Mark Wallace before becoming Azharullah's first victim.
Matthew Spriegel (2-22) then removed Chris Cooke (four) and Wallace (19) before Goodwin came to the fore.
Azharullah took his second wicket when Graham Wagg (14) knocked the bails off with his bat and the Pakistani seamer then dismissed both Nathan McCullum (five) and Goodwin in the final over.
Northants lost Kyle Coetzer (two) in the second over when he hit Allenby (1-33) to Alex Jones at deep square leg as the hosts fell behind the run-rate early on.
Richard Levi then departed on 24 when Dean Cosker's delivery spun into his off stump before Wakely was dropped on 13 by Goodwin at backward point off the same bowler.
White went past 50 off 43 balls by blasting a six down the ground off Michael Hogan as Northants clawed their way back into contention in the last four overs.
Wakely then completed his half-century off just 35 deliveries, but White was run out by Nick James at backward point before Steven Crook's four off Hogan sealed the win.