Middlesex's Dawid Malan struck 99 as the Panthers chased down 248 to beat Somerset by four wickets at Lord's and go third in Group C of the Yorkshire Bank 40.
Set 248 to win from their 40 overs, after Somerset posted 247/7, the left-handed Malan struck 99 from 100 balls to continue his fine form of late in the competition, before he edged one to Alex Barrow behind the stumps off the bowling of Craig Meschede in the 31st over.
The 25-year-old has been instrumental for Middlesex in their last three YB40 matches, after an unbeaten 80 against Leicestershire and 96 against Yorkshire.
At 185/5 Middlesex could have wobbled in their pursuit of victory, but skipper Neil Dexter (39 not out) and Ollie Rayner (12 not out) - who took 3/31 in Somerset's innings - were on hand to make sure there were no late hiccups as they finished on 250/6 with five balls to spare.
The victory was the Panthers third on the bounce in the YB40 competition and puts them third in Group C, two points behind leaders Gloucestershire and just one behind Somerset.