Essex 125 for 4 (Westley 37*, Walter 36*, Sanderson 3-15) trail Northamptonshire 369 (Keogh 172, Broad 56*) by 244 runs

Essex started their first innings needing at least 400 if rivals Surrey were bowled out for less than 250 in their game at Southampton, but Sanderson made short work of their top order, removing Alastair Cook, Nick Browne and Dan Lawrence in a nine over spell, while conceding just 14 runs.

They rallied to 125 for 4 by the close of play, still trailing by 244 runs to just about keep their challenge alive following Surrey's collapse at the Ageas Bowl. Surrey though require only a draw to clinch another Championship. Essex, meantime, are pinning their hopes on Hampshire beating Surrey, and then finding a way to somehow earn four batting points tomorrow and beat Northamptonshire.

Sanderson (3 for 15) made the most of overcast conditions under lights, bowling a metronomic line and length and extracting prodigious seam movement which drew Essex's batters into repeatedly playing and missing outside off-stump. Along the way he reached 350 first-class wickets in Northamptonshire colours when he dismissed Cook.

Wickets continued to fall at the other end. Tom Taylor, playing his final match for Northamptonshire before moving to newly-promoted Worcestershire, came out with real intent. He smashed Matt Critchley down the ground for six, but when he attempted to repeat the shot, he could only pick out Porter at mid-on.

The new ball did the trick for Porter who got one to seam back and knock Sanderson's middle stump out of the ground before enticing the edge from Jack White, Alastair Cook taking a tumbling catch at slip.

In reply, Browne started briskly but drove loosely to a fuller ball from Sanderson and was caught behind by keeper Lewis McManus. Cook played a beautiful extra cover drive off Sanderson but was undone when the Northamptonshire stalwart got one to nip back and send his off-stump cartwheeling.

Dan Lawrence, playing his final match for Essex before he joins Surrey, fell soon after lunch when he played away from his body to another ball from Sanderson which seamed away, McManus again taking the catch.

Critchley (17) saw off Sanderson, eventually getting hold of one from Taylor, guiding it safely down to third to bring up Essex's 50 in the 16th over and driving White through midwicket for another boundary. But when Northamptonshire skipper Luke Procter pitched one up, Critchley played across the line trying to work the ball to leg, only to have his off-stump knocked back.

White was finding plenty of movement off the seam too and drew Paul Walter into edging behind with just 1 to his name, only for Karun Nair to drop the ball at first slip. Walter started to find the boundary, driving fluently through extra cover.

Tom Westley, who had put on 33 with Critchley, played sweetly off his legs early on, but became becalmed, scoring just 1 out of an unbeaten partnership of 27 with Walter before bad light and rain stopped play with Essex on 95 for 4, still trailing by 274 runs.

After the resumption, Walter started to stroke the ball sweetly down the ground, but Essex's scoring remained doggedly below three an over, putting them a long way behind the rate required to secure the three batting bonus points they need.