Truly fine weather removed the hazy, swinging conditions in which, on the opening days, each side had fallen just short of 200. But it was as if that figure was a glass ceiling in Worcestershire minds as they kept finding ways to get out, eventually stumbling to a poor 179.

That ceiling was then removed as Durham went rather easily to 64 for one, indicating an early finish today - if the weather holds - and an underpinning of the champions' lead.

Worcestershire's second-innings struggle again had one bowler at the heart of its troubles. Liam Plunkett followed his career-best six for 63 in the first innings with, in less helpful conditions, five for 56, giving him comfortably his best match figures of 11 for 119.

Again, he grew into his work, so that by the conclusion of his 24 overs - almost twice as many as any of his fellow pace bowlers - Durham were relying almost entirely on his aggression and unpredictable speed to mop up a resistant lower order.

His first wicket came from a loose slash to deep point by Moeen Ali, but later victims showed clear signs of unease. One was Gareth Batty, who played no shot to a ball that uprooted his off stump. Another, Alexei Kervezee, batted all morning in a sound, composed manner and reached 66, the top score of the match, only to became unsettled by Plunkett. Aborting a hook too late, he spooned a catch to the wicketkeeper.

Another batsman who fell playing no shot was Ashley Noffke, in his case falling leg-before to Ian Blackwell's straighter ball.

At 124 for eight, a three-day finish looked possible before Kabir Ali succeeded with unconventional resistance, heaving in pantomime style at Plunkett while offering an exaggerated dead bat to Blackwell's gentle spin. He had made 30 off 71 balls when Plunkett swept away the last of his partners.

Worcestershire: First Innings 193 (A A Noffke 50; L E Plunkett 6 for 63)
Second Innings (overnight 0-0)
D K H Mitchell c Di Venuto b Davies 15
A N Kervezee c Mustard b Plunkett 66
M M Ali c Coetzer b Plunkett 10
B F Smith c Coetzer b Thorp 3
D A Wheeldon c Di Venuto b Claydon 0
A A Noffke lbw b Blackwell 11
*G J Batty b Plunkett 4
Kabir Ali not out 30
†J P T Knappett c Mustard b Blackwell 1
C D Whelan b Plunkett 21
M S Mason c Thorp b Plunkett 5
Extras (lb 5, nb 8) 13
Total (74 overs) 179
Fall of wickets: 1-36, 2-57, 3-66, 4-71, 5-108, 6-116, 7-117, 8-124, 9-169.
Bowling: Claydon 11-0-50-1; Thorp 13-6-27-1; Davies 10-2-19-1; Plunkett 24-6-56-5; Blackwell 16-7-22-2.

Durham: First Innings 194 (P Mustard 63 not out; K Ali 6 for 68)
Second Innings
M J Di Venuto not out 43
K J Coetzer c Knappett b Noffke 15
*W R Smith not out 3
Extras (b 2, lb 1) 3
Total (1 wkt, 21 overs) 64
Fall of wicket: 1-47.
Bowling: K Ali 4-0-19-0; Mason 5-2-12-0; Noffke 7-2-11-1; Batty 5-1-19-0.
Umpires: R J Bailey and N G B Cook.