Middlesex moved a step closer to taking over at the top of the LV= County Championship Division One table by dominating day three against Northamptonshire.
Inspired by a superb 163 not out from Neil Dexter, the visitors were able to declare their first innings on 543-7 at Wantage Road, meaning they held a commanding lead of 260.
Struggling Northants limped to 88-4 by the close, Tim Murtagh dismissing James Middlebrook with the second ball of the innings before Toby Roland-Jones claimed two wickets, taking his tally in the match to eight.
Joe Denly then capped off an excellent day, both for himself and his county, by getting Martin Spriegel caught for 36 to what turned out to be the last delivery.
The former Kent batsman had earlier shared in a record fourth-wicket stand of 158 with Dexter, making 70 as the pair pushed Middlesex further ahead of their beleaguered opponents.
Dexter went on to post a career best in first-class cricket, his century including three sixes and 19 fours. Roland-Jones weighed in with a rapid 60 off a mere 30 deliveries, with his departure leading to Chris Rogers declaring.
Durham dig in
Also in the top tier, a century stand from Mark Stoneman and Mark Richardson for the second wicket helped Durham erase a first-innings deficit on day two against Somerset.
Opener Stoneman reached the close unbeaten on 60 while Richardson was 57 not out, the pair having come together after Keaton Jennings had been caught off the bowling of Alfonso Thomas.
Durham had already showed fighting spirit with the ball, dismissing their hosts for 234 at Taunton to leave them only trailing by 79 after each county had batted once.
Alviro Petersen's fluent 78, plus a quick-fire 45 not out from Craig Overton helped Somerset edge ahead, though their cause was not helped by a middle-order collapse that saw them slip from 132-3 to 154-7.
Mark Wood was the star turn with the ball for the reigning champions with fine figures of 5-37; he was ably supported by Chris Rushworth, who picked up 4-70 the day after it was announced he has signed a new three-year contract.