Durham 213 and 126 for 6 (McLaren 3-35, Edwards 3-39) lead Hampshire 251 (Ervine 47, Hastings 4-49, Onions 4-61) by 88 runs
After looking doomed a month ago, Hampshire stepped up their escape act in LV= County Championship Division One as they closed in on a second successive win at Chester-le-Street.
Ryan McLaren continued his excellent debut by scoring 30 and adding three wickets to his four in the first innings as Durham struggled to 126 for 6, a lead of 88. There were also three catches for former Durham captain Will Smith at gully to add to his useful vigil with the bat.
The momentum has shifted markedly since Hampshire clung on for a draw with nine wickets down when these sides met at the Ageas Bowl in July and a fourth successive home defeat looms for Durham.
While his team-mates have been in decline, Graham Onions has struck form recently and was kept out only by the sheer determination of Smith and Liam Dawson.
After resuming on 77 for 3, they scored only two runs in the day's first eight overs, but laid the platform for others to press on and earn a useful lead of 38 before Hampshire were all out for 251.
After taking all three wickets the previous evening, Onions beat the bat several times but Durham's luck changed when he made way for John Hastings. Dawson edged a pull to wicketkeeper Michael Richardson to depart for 25, ending the dogged stand of 58 in 32 overs, then Smith was caught at long leg for 38.
They were careless exits after the hard labour, but it began to bear fruit as Sean Ervine added 48 in 10 overs with Adam Wheater. Onions returned to have Wheater lbw before McLaren also batted fluently until Hastings yorked him.
Gareth Berg played back and edged to second slip and Hampshire were still six behind on 206 for 8 when Devon-born debutant Ryan Stevenson went in. He confidently made 30 of the 44 added for the last two wickets and as he had already shown his capabilities it was a surprise when Ervine slogged across a straight ball and was bowled for 47 to give James Weighell his maiden first-class wicket.
As in the first innings, Durham swiftly lost their top three. Jack Burnham was missed at second slip by Dawson, only to offer the same fielder another chance without addition.
Mark Stoneman sliced a drive to gully and Scott Borthwick's fierce cut also flew straight to Smith. Richardson was bowled by a shooter from Fidel Edwards, before Paul Collingwood and Gordon Muchall went for their shots in adding 42.
McLaren returned to have Collingwood lbw, pushing forward, for 37 and Muchall went for 32 when a thick edge off Edwards was accepted by Smith just before bad light ended play with four overs left.