Left-arm spinner Murali Kartik's five-wicket haul in the second innings could not resurrect Middlesex's fortunes as they lost to Derbyshire by 15 runs in a four-day county cricket match at Southgate.
Kartik, who took two wickets in the first innings, polished off the tail to return figures of five for 38 off 25.2 overs in the second innings and restrict Derbyshire to 199.
Derbyshire, who scored 340 in their first essay of the Division Two match, gained an 82-run first innings lead over the hosts by knocking them over 258.
Chasing a victory target of 282, Middlesex were dismissed for 266 as half-centuries by skipper Ed Smith (65) and Andrew Strauss (53) went in vain.
Karthik failed with the bat in both innings, getting a duck and two.