Warwickshire grabbed four wickets for four runs in the space of 10 deliveries to assume control of their clash with Middlesex at Uxbridge.
Warwickshire batted for much of Tuesday's opening two sessions before acting skipper Varun Chopra's declaration gave them a session and eight overs of day two in which to make inroads into the Middlesex top-order.
Having featured in stands of 113, 113, 55, 100 and 66 Chopra - who was dropped twice on the opening morning before even scoring a run - finally said enough soon after 3pm having batted nine-and-a-half hours for his double century.
After Chopra declared unbeaten on 228 and with his Warwickshire side well placed on 486-6, Middlesex crumbled to 28-4 before launching a comeback after tea to reach 177-4 at the midpoint of the game.
Having fielded in blazing heat for the best part of 10 hours, Middlesex quickly wilted in the face of some impressive new ball bowling by the reigning champion's attack.
Dawid Malan (two) fenced at one from left-armer Keith Barker and nicked to third slip then, four balls later, Joe Denly (four) was squared up by a leg-cutter to edge to the same fielder.
Without addition to the total Sam Robson (16) followed a lifting delivery from Chris Wright to pick out Jeetan Patel for a third successive catch at third slip then Neil Dexter feathered Wright's next delivery through to the keeper to go for a first ball duck.
John Simpson survived Wright's hat-trick ball and, after the tea break, joined forces with Adam Voges to frustrate the Bears' bowlers throughout the third session.
Voges, the Australian right-hander, posted a 70-ball 50 with eight fours and went in at stumps on 80 not out, while Simpson (50*) reached the landmark from 86 balls and with nine fours in an unbroken fifth-wicket stand of 149.
Even so, the hosts will go into day three requiring a further 160 runs to avoid the follow-on.