Nathan Buck continued his excellent start with Northamptonshire by taking a career-best six for 34 as wickets tumbled in the Specsavers County Championship match at Chester-le-Street.
Durham, still on minus 24 points at the foot of division two, were dismissed for 166 then had Northants rocking on 28 for three before Max Holden and Chesney Hughes steered them to 59 for three at the close.
At 26, Buck is starting to fulfil his undoubted potential with his third county and is the joint second highest wicket-taker in division two with 27.
It was inevitable that Northants would bowl when play began at 1.10 following rain. Heavy cloud persisted for most of the day, and the tinge of green in the pitch could hardly have been intended to suit a home attack shorn of five seamers.
Paul Coughlin and Irishman Barry McCarthy opened the bowling for Durham with 22-year-old Scot Gavin Main in support, making his second Championship appearance three years after the first.
Northants' four seamers maintained a probing accuracy on a day when no wickets fell in the first ten or the last six overs, with the 45 inbetween yielding 13, nine of them to edged catches. Northants had five slips at one stage.
The going was always tough, but the Durham openers put on 30 before Stephen Cook's disappointing form continued with an edge to second slip off Rory Kleinveldt.
Then Buck struck with his seventh ball, which lifted and left Keaton Jennings for a catch behind.
Buck bagged two of the three lbws and the only catch in front of the wicket completed his second successive five-for when extra bounce found the shoulder of McCarthy's bat and the ball lobbed to mid-off.
With 24 overs to bat, Northants lost Rob Newton in the third over, when Coughlin's pace produced a flying edge to first slip.
Alex Wakeley and Rob Keogh were both strangled down the leg side off McCarthy, although Keogh's was more of an authentic glance, brilliantly pouched by the diving Stuart Poynter.
Ex-Derbyshire man Hughes, given his chance by the absence of Ben Duckett and the concussed Richard Levi, looked as confident as any batsman in his unbeaten 16. Bad light ended play with eight overs still to bowl at 6.40.
Speaking at the close of play, stand-out performer Buck said: “It's about time I took a six-for, but if I can do that it shows it must be doing a bit. The ball bounced a bit and there was good carry. It swung quite a bit at times, but didn't nip that much off the pitch.
“The way Max Holden stuck in at the end shows what can be done and it's a big day for us tomorrow. The way we lost our last two wickets was unlucky, but Chesney was looking good.”