Ben Duckett hit his fourth century of the season to help Northants halt a Surrey surge at the Kia Oval.
David Ripley’s men were bowled out for just 110 in reply to Surrey’s 410, but Duckett and skipper Alex Wakely showed fight to stem the tide.
Duckett ended day three unbeaten on 116, while Wakely was 93 not out at the close of play, leaving Northants needing 77 runs to avoid an innings defeat.
The Curran brothers, Tom and Sam, whose late father, Kevin, played for Northants did the damage in the first innings, with Tom taking seven for 35 and Sam picking up three for 46.
It was the first time two brothers had shared 10 wickets in an innings in the Championship since Jack Oakes took five for 68 and Charlie Oakes five for 35 for Sussex against Somerset at Taunton in 1950.
Tom Curran struck again with the third ball of Northants’ second innings but just when it looked as though they could be beaten inside two days – the first day was lost to rain – Duckett and Wakely showed the spirit and application that had been badly missing.
Play had started 30 minutes late after morning rain but Sam Curran, who hit nine fours and a six, and Gareth Batty made up for lost time by taking their ninth-wicket stand to 56 in 10 overs.
Then it was Curran senior’s turn. Swinging the ball at a decent pace, he tore into the Northants batting, having Duckett caught behind, Wakely lbw and Rob Keogh caught at second slip.
Sam nipped in to claim Rob Newton lbw and after that only Josh Cobb held the brothers up with an unbeaten 29 as they ran through the tail. It was the second time Tom had taken seven wickets this season and his fifth haul of five wickets or more.
Centurion Duckett said: “Tom Curran was very good in that first innings. He just tries to bowl straight and nip it away. He’s been doing it all season so it’s not a one-off.”