Middlesex 282 and 256 (Robson 52) beat Derbyshire 205 (Bamber 5-41) and 221 (Godleman 70, Critchley 58, Roland-Jones 5-36) by 112 runs
Seamer Toby Roland-Jones marked his return from injury with a decisive five-wicket haul as Middlesex finally broke Derbyshire's resistance to triumph by 112 runs at Lord's.
Roland-Jones, making his first appearance after a four-month absence due to knee surgery, delivered a spell of three wickets in 10 balls that included the scalp of Derbyshire captain Billy Godleman and finished with figures of 5 for 36.
Godleman had managed to keep the visitors in the hunt for a 334 victory target with his innings of 70, his best of the season, after two early wickets fell to opposite number Tim Murtagh.
Matt Critchley's knock of 58 also proved to be in vain as Derbyshire were dismissed for 221, leaving them as the only side still without a win in the LV= Insurance County Championship this season.
Murtagh gave Middlesex an immediate lift with his first ball of the morning, pinning Tom Wood in front of the stumps and he added the wicket of Leus du Plooy soon afterwards.
The left-hander, who had just swung Murtagh to the midwicket boundary, attempted to repeat the shot to a ball outside off stump and dragged on to leave Derbyshire in difficulties at 60 for 3.
However, Critchley proved harder for Middlesex to shift, with Martin Andersson dispatched for a couple of crisp fours as he and Godleman put together a partnership of 80 either side of lunch.
The fourth-wicket pair succeeded in bringing Derbyshire's target below 200 - but the turning point came when Godleman pulled Roland-Jones towards long leg and Andersson ran in to hold a perfectly-judged diving catch.
Critchley might have followed his captain later in the same over, miscuing the ball high behind square only for it to land between three fielders, but Derbyshire were soon six down as Roland-Jones removed Alex Hughes and Brooke Guest in successive deliveries.
Anuj Dal - who had hit a valuable 48 in the first innings - produced some attacking shots to reach 19 before he was unluckily run out at the non-striker's end, with Andersson deflecting Critchley's drive onto the stumps.
That appeared to unsettle Critchley, who attempted a careless pull shot off Andersson just two balls later and sliced into the hands of second slip.
It was left to Roland-Jones to wrap up Middlesex's success and he did exactly that, having Sam Conners caught at short midwicket before knocking out Alex Thomson's off stump.