Worcestershire's ninth wicket pair of Brett D'Oliveira and Jack Shantry added an unbroken 74 after Moeen Ali fell two short of his century on the third day of the LV = County Championship match with Essex at Chelmsford.
The county reached 238-8 by lunch – still trailing by 109 runs – after resuming on 113-2.
Moeen resumed on 70 and a had a let off on 91 when Tom Westley dropped a chance at second slip off David Masters.
But after making a fine 98 he top-edged a delivery from Graham Napier to Greg Smith at mid wicket.
That was the third wicket of the over for Napier in a destructive morning spell which brought him five wickets.
Moeen and Tom Fell took the overnight score to 136 before the latter on 21 was bowled by David Masters.
His determined innings spanned 80 balls and 95 minutes and the partnership with Moeen was worth 82 in 28.1 overs.
Napier came into the attack for Jesse Ryder and picked up two wickets in his first over when he trapped Alexei Kervezee (0) and Tom Kohler-Cadmore (0) lbw with the fourth and sixth balls of the over.
The Essex paceman then struck with the first, second and fifth deliveries of the 54th over.
Ben Cox (13) was caught behind, Joe Leach (0) was adjudged lbw and then Moeen's fine knock came to an end.
The ninth wicket pair of D'Oliveira and Shantry produced a series of attacking shots.
Shantry picked up three boundaries in an over from Napier and a six by D'Oliveira off Westley brought up the 50 partnership.
D'Oliveira was unbeaten on 35 and Shantry 30 at the interval.
