Middlesex 141 for 5 (Morgan 43) beat Somerset 137 (Allenby 64, Roland-Jones 3-24) by five wickets
Eoin Morgan top scored with 43 as Middlesex boosted their hopes of a NatWest T20 Blast quarter-final place with a five-wicket win over Somerset at Taunton.
The hosts were bowled out in 19.3 overs for a paltry 136 after winning the toss as their desperately disappointing group campaign yielded an eighth defeat. Jim Allenby top-scored with 64, while Tony Roland-Jones claimed three for 24.
There were two wickets each for James Fuller, Harry Podmore and Nathan Sowter. Middlesex coasted to victory with five balls to spare as Morgan, Dawid Malan (24), George Bailey (21) and John Simpson (23 not out) led the way to the modest target.
Somerset's embarrassment was complete when a no-ball for not having enough fielders in the circle helped tilt the game towards Middlesex in the closing stages.
Somerset's innings was as grey as the weather. They were given a reasonable start by Allenby and Mahela Jayawardene, who took the score to 49 at the end of the six-over powerplay.
Then Jayawardene was caught behind making room to cut Podmore and from that point the innings meandered, providing precious little excitement for home supporters in the crowd.
Peter Trego departed to his first big hit, caught at long-off to give leg-spinner Sowter his first wicket and, although Allenby moved to a half-century off 38 balls, with 7 fours and a six, Somerset badly lost momentum.
Johann Myburgh did his best to inject some urgency and hit the only other six of the innings before being caught attempting another. Tim Rouse's first team debut ended on nine when he was bowled by Fuller.
Roelof van der Merwe failed to clear the short boundary on the town side of the ground and fell to Roland-Jones, who followed up by dismissing Allenby and Lewis Gregory with the fifth and sixth balls of the same over.
It was an all too familiar story for Somerset fans as only three batsman managed double figures.
Under no pressure to score quickly, Middlesex openers Nick Gubbins and Dawid Malan still took 16 off the third over, bowled by Gregory.
They had added 29 in 3.4 overs when Gregory took a sharp catch at mid-wicket off van der Merwe to dismiss Gubbins for 13.
Middlesex then got bogged down themselves. Malan made room only to carelessly slash a catch to deep cover off Josh Davey, Somerset's most impressive bowler.
After ten overs the score was only 54 for two as Morgan and Bailey began watchfully. Morgan hit the first six of the innings off Max Waller in the 12th over.
Bailey fell with the score on 91, caught at deep mid-wicket off Davey, but by then Morgan was starting to cut loose and he collected another maximum off van der Merwe in the 16th over as Middlesex closed in on victory.
The England batsman was visibly frustrated over being caught at long-off in the 18th over to give Waller a wicket. And when James Franklin hit a Gregory full-toss straight to mid-off with nine needed from eight balls Middlesex hearts beat a little faster.
But a no-ball awarded against Gregory for too many fielders outside the ring followed by a Ryan Higgins boundary quickly eased any nerves and a Simpson six off the first ball of the final over settled the outcome.
Allenby said: "What happened with the last ball of the 19th over was that we knew we were running short of time and needed to get into position quickly.
"I probably wasn't quite clear enough in the field we needed to set and it was all a bit of a rush. The no-ball was called because we only had three men inside the circle.
"Defending nine off the last over would have been tough, with John Simpson in form he has been showing, but there would have been a chance. As it turned out, the free hit went for four and the first ball of the last over for six, so we will never know what might have been."