County champions Surrey remained on course to claim a fifth red-ball win of the season despite prolonged resistance from Worcestershire half-centurions Gareth Roderick and Kashif Ali.
The County Championship Division One leaders achieved their first objective in claiming the final three Worcestershire first-innings wickets in the morning session as the Pears were bowled out for 212, despite resistance from Jake Libby (77), Ben Allison (21) and Adam Finch (27).
With a lead of 278, Surrey duly enforced the follow-on and then removed Libby second time around for 28 going for an expansive drive as he was bowled via an inside edge to become the first of three wickets for Jordan Clark.
Roderick and Kashif then dug in to add 135 from 34 overs in relatively untroubled fashion for the second wicket.
They completed their century stand off 167 balls, but three wickets then fell in three overs to turn the game firmly back in Surrey’s favour in the final session.
First Roderick edged Clark and was caught low down at slip, then seven balls later Kashif went to pull England contender Gus Atkinson and lobbed up a simple catch to square leg.
Worse was to follow for the Pears when Rob Jones went for a duck in the next over to complete a slump from 168-1 to 172-4.
But there was only one more wicket before the close when Ethan Brookes nicked through to England keeper Ben Foakes.
The hosts will resume again in the morning on 207-5, with Adam Hose on 20 and Matthew Waite on five as winless Worcestershire bid to avoid a sixth defeat in eight games.
