Somerset 404 (Bartlett 121, Abell 77) beat Middlesex 175 (Simpson 57*, Henry 5-45) and 216 (Stoneman 60, Overton 5-46) by an innings and 13 runs
Craig Overton recorded his best figures this summer to propel Somerset to their first LV= Insurance County Championship win of the campaign as they crushed Middlesex by an innings and 13 runs at Lord's.
Overton finished with five for 46, supported by fellow seamer Peter Siddle's effort of three for 57, to dismiss the home side for 216 second time around, with more than four sessions to spare.
Mark Stoneman, who occupied the crease for almost three hours in compiling 60, was the only man to register a half-century in a Middlesex side who have managed to post in excess of 250 only once this season.
Somerset's victory was only their second red-ball success away from Taunton in more than two years, the other coming against neighbours Gloucestershire at Bristol last summer.
Stoneman and Stephen Eskinazi, who resumed on a steady 81 for one, ground it out for the bulk of an attritional first hour, with almost five overs from Matt Henry and Overton yielding just a single leg-bye.
Although Stoneman tucked Overton away for a single soon afterwards to bring up his second half-century of the summer, Middlesex's solid base was swiftly demolished by a fiery spell from Siddle at the Pavilion End.
The seamer's first delivery was carved for four by Eskinazi, but his second jagged back to clip the Middlesex vice-captain's off bail and his departure for 28 signalled a familiar middle-order collapse.
Stoneman - bowled by an unplayable Henry delivery first time around - was unlucky to fall victim to another ball of similar quality from Siddle, which seamed and careered into his off stump.
Somerset collected three more wickets in the space of 21 balls before lunch, with Overton accounting for Max Holden and John Simpson to sandwich the first delivery of Jack Leach's spell that pinned Robbie White leg before.
Luke Hollman and Ryan Higgins displayed some fighting spirit after the interval, with the left-hander driving Henry twice off the back foot to the short boundary as he contributed 28 to their seventh-wicket partnership of 44.
Although Hollman was caught at third slip, Toby Roland-Jones took up the baton by giving Leach the charge and also hammered Overton over long-on for two fours in a cameo of 27 from 24 balls.
But Overton had the final word, bowling the Middlesex skipper before completing his side's win as Higgins (31) hooked him into the safe hands of Lewis Gregory at long leg.