A nightmare over cost Northants dear as they were dumped out of the Royal London One-Day Cup in dramatic fashion by Surrey.
Richard Gleeson sustained an injury two balls into the 21st over and skipper Alex Wakely then conceded 24 from the deliveries he bowled.
Kumar Sangakkara, who had been dropped on seven by Ben Duckett, was the main beneficiary and the Sri Lanka star was to secure the victory in the most frantic of finales as he hit the final ball for four to seal a one-wicket win for his side. The 38-year-old finished unbeaten on 130 from 145 balls.
Northants had made it to 276 all out as Rory Kleinveldt cracked a superb unbeaten 76 from 62 balls, while Josh Cobb made 66 from 63 earlier on.
But it was to be an agonising day for the Steelbacks and they will hope it now doesn’t prove to be a disastrous one, with NatWest T20 Blast finals day beckoning on Saturday.
Gleeson looks to be a big doubt for the 11am semi-final clash with Nottinghamshire Outlaws at Edgbaston, and that would leave Northants shorn of their stand-out bowler.
The pace ace had impressed early in this match as he took the wicket of Steven Davies to leave Surrey two for one.
But Sangakkara and Jason Roy rebuilt and despite a shocking late wobble, during which they lost four wickets for six runs, Surrey just had enough to squeeze home.
Northants had won the toss, with captain Wakely calling correctly for the first time in the competition. He had lost all eight tosses in the group stage.
The Steelbacks, so often impressive chasers, opted to try to set a score but after Richard Levi fired a few early boundaries, the hosts were in trouble.
Levi went for a run-a-ball 20 as he was caught by James Burke off the bowling of Jade Dernbach, and Dernbach soon had a second wicket as Duckett departed for seven.
Steelbacks’ 44 for two was to be 73 for three when Rob Keogh was caught by Sam Curran off the bowling of Stuart Meaker.
And Northants were constantly having to rebuild, with wickets being lost just as they were gathering momentum.
That theme was to continue as Tom Curran bowled Josh Cobb, who had made an impressive 66, which included seven fours and three sixes.
Wakely had also found the boundary with ease on a few occasions, but he went for 45 as he was bowled by Sam Curran.
Rob Newton had hit a double hundred in the County Championship draw with Leicestershire, but failed to continue his fine form as he went for just one off Burke.
Dernbach then struck for the second time to remove Adam Rossington, who had made 25, before Graeme White went for six, with wicketkeeper Ben Foakes taking a fine catch low to his right off Meaker.
The Steelbacks were struggling, but Kleinveldt was starting to shoulder the burden and he kept firing despite the loss of wickets at the other end.
Gleeson was bowled by Tom Curran to leave Muhammad Azharullah as the final man to keep Kleinveldt company.
And the tail-ender was to do so superbly as he blocked well and provided ample strike for Kleinveldt, who feasted on the Surrey bowling.
The big South African was given a standing ovation as he ended unbeaten on 76 with Azharullah having been caught and bowled by Dernbach to end the innings.
The Steelbacks had a big job on to defend their 276, but Kleinveldt and Gleeson started strongly with the ball.
And Gleeson was to strike in his first over, bowling Steven Davies for a duck, which saw star men Roy and Sangakkara paired in the middle for Surrey.
Sangakkara made a tentative start and he was lucky not to go as Duckett dropped a catch he would have expected to take at gully off Gleeson.
The Steelbacks were soon ruing that missed chance as the Sri Lankan batsman started to tick along nicely, with Surrey taking control.
Roy made 42 before Azharullah bowled him, giving Northants a much needed breakthrough to leave the away side on 88 for two after 14 overs.
Rory Burns was next in, but he didn’t stick around for long as he provided White with a cheap wicket, with the batsman caught by Wakely.
But Sangakkara helped Surrey to rebuild, reaching his 50, and the Steelbacks were dealt a huge blow soon after as Gleeson was forced off the field.
The bowler appeared to have sustained a side injury and, to compound the misery, Wakely took over and bowled a high no ball, which was flashed away for six.
It was unravelling rapidly for the Steelbacks, with the over eventually going for a total of 25 runs, putting Surrey firmly in control.
White did return to get rid of Foakes, having the wicketkeeper-batsman caught behind for 16, but Sangakkara was still there, piling on the pain for the Steelbacks.
He was to reach his hundred, just after Sam Curran had been dismissed by Cobb for 26, and Surrey were still cruising to victory.
Tom Curran came in and struggled to get in the groove as he made 13 off 28 before nicking behind to give Cobb a Curran double.
Things started to get slightly interesting when Burke top edged one and was caught behind off Kleinveldt, leaving Surrey needing 38 from 30 balls with three wickets remaining.
Gareth Batty was next in, but he only made three before being run out by Rossington as he tried to take a single that was never on.
The County Ground crowd were getting into it, with Surrey needing 28 from 20 balls, but Dernbach came in as last man and managed to find a four before getting Sangakkara on strike for the final over.
Azharullah was the man with the responsibility of bowling it for the Steelbacks and he forced Sangakkara to take a single off the first ball.
Dernbach then took a single of his own before Sangakkara hit the shot of the match, ramping the ball over Rossington for six.
It left Surrey needing four from three balls and after the Steelbacks came so close to running out Dernbach, Sangakkara hit a four from the final ball to confirm the win.
Steelbacks: Levi, Cobb, Duckett, Wakely (c), Keogh, Rossington, Newton, Kleinveldt, White, Gleeson, Azharullah.
Surrey: Roy, Burns, Sangakkara, Davies, S Curran, T Curran, Burke, Foakes, Batty (c), Meaker, Dernbach.