Middlesex 364 for 6 (Robson 106, Gubbins 90) beat Somerset 246 (Azhar 46, Sowter 3-50) by 118 runs
Sam Robson recorded his maiden white-ball century as Middlesex crushed Somerset by 118 runs at Radlett to reignite their Royal London One-Day Cup prospects.
Robson, making his first appearance in the competition since he limped off with a hamstring injury against Hampshire almost exactly two years ago, top scored with 106 from as many balls.
He shared an opening partnership of 138 with Max Holden (45) and, supported by a fluent knock of 90 from Nick Gubbins, set up Middlesex's third-highest 50-over total of 364 for 6 after they had been put in to bat.
Somerset, who have now lost twice after winning their first four South Group fixtures, were unable to build any significant partnerships and were bowled out for 246 in 43.4 overs.
Holden was the more aggressive of Middlesex's opening pair as they made a solid start, but Robson gradually eased into his stride, picking the gaps and hitting Josh Davey for successive leg-side fours.
Robson particularly relished the introduction of Tim Groenewald, heaving the Somerset seamer over the top for four and six in successive deliveries and following that up with 14 off his next over.
It was part-time bowler Azhar Ali who finally made the breakthrough, with Holden - who had earlier survived a chance to Tom Abell at midwicket - driving the leg-spinner into the hands of long on.
Gubbins moved up the order to three and made his attacking intent clear, looking particularly strong on the leg side, while Robson offered just one chance at 90, with Azhar unable to cling on to a return catch.
But the Middlesex opener motored on to reach his ton from 99 deliveries, taking advantage of a misfield to run two before eventually pulling the first ball of Craig Overton's second spell to Roelof van der Merwe at mid-wicket.
Gubbins looked well-placed to follow Robson into three figures, but his innings of 90 from 59 balls came to an end when he swung van der Merwe into the hands of Lewis Gregory on the boundary.
Middlesex maintained their momentum during the later overs, with John Simpson (32) and Stevie Eskinazi (30) adding 60 before some powerful blows from George Scott (20*) and Toby Roland-Jones (22*) hauled them beyond 350.
Two sharp catches, from Nathan Sowter and Robson respectively, enabled the home side to make early inroads when Somerset replied, with Tom Banton (3) and Peter Trego (12) back in the pavilion before the end of the Powerplay.
James Hildreth briefly threatened to make a significant impact, hitting 18 from 19 balls before he played on to James Harris, while Abell (8) was run out at the non-striker's end when Scott deflected Azhar's drive onto the stumps.
Sowter claimed 3 for 50, striking with his second delivery by persuading George Bartlett (17) to sweep to backward square leg before Azhar - who had batted tidily for 46 - was caught behind swishing at Tom Helm.
Van der Merwe threw the bat for a swift 38 and, although Groenewald (28) and Davey (23*) delayed Middlesex with a last-wicket stand of 50, Roland-Jones wrapped up victory when the former scooped him to mid-wicket.