Champions Durham in charge
Durham are pushing for an opening win over Northamptonshire in the defence of their Championship title after establishing a lead of 252.
Seamers Usman Arshad and Jamie Harrison shared seven wickets as the hosts were bowled out for 378, with 97 from Matt Spriegel.
Then Durham were able to push on to 178 for five and open up the possibility of a challenging declaration on the last morning, despite four for 39 from veteran off-spinner James Middlebrook.
Northamptonshire lost four wickets before lunch, having resumed on 200 for three.
The introduction of leg-spinner Scott Borthwick worked immediately for Paul Collingwood when Rob Newton edged a drive to the Durham captain at slip.
That ended a stand of 65 with Spriegel, who was soon having a few scrapes against Borthwick - including a minor scare before he reached his 50, when a half-chance off the full face of the bat was not held at short-leg.
Instead, Arshad took two wickets in successive overs - Andrew Hall lbw aiming to leg and David Willey mistiming to cover.
A typical Stephen Crook counter-attack followed, but it was short-lived thanks to another successful bowling change, when the occasional medium-pace of Keaton Jennings did the trick just before the second new ball was available - Crook lbw back on his stumps.
Graham Onions and Chris Rushworth were unable to make a breakthrough, the England seamer frustrated by a series of unsuccessful lbw appeals against Spriegel.
Eventually, though, Arshad (four for 78) stopped Spriegel becoming the first centurion of the match - the left-hander, who had just hit successive boundaries, going after a wide ball with his eyes on another four to reach three figures but instead edging behind.
Spriegel had nonetheless made his highest first-class score since moving north from Surrey.
Harrison (three for 83) then had David Murphy edging to slip, and Arshad his final wicket when Azharullah did likewise to be last out.
Durham had obvious designs on quick runs second time round, but needed to lay a platform - all the more so after Mark Stoneman fell cheaply, for the second time in the match, in only the third over.
Maurice Chambers got a little extra bounce to have the left-hander fending to slip, and Middlebrook then had Jennings caught-behind pushing forward.
Borthwick and Michael Richardson (53no) - on his way to his second half-century of the match - shared a stand of 70 until the former was also caught-behind off the off-spinner, cutting this time.
Middlebrook bagged his third wicket when Phil Mustard missed a sweep.
However, some handy late blows from Collingwood, before he too fell to Middlebrook, ensured he and Durham still had the leeway to dictate the remaining course of this match.