Dawid Malan's unbeaten 113, backed up by an impressive bowling display, earned Middlesex Panthers a 19-run Duckworth/Lewis win against Gloucestershire Gladiators at that kept alive their hopes of qualifying for the Yorkshire Bank 40 semi-finals.
Gloucestershire's own chances of making it out of Group C received a heavy blow as they could make only 186 for nine chasing an adjusted target of 206 after Middlesex had posted 206 for five at Lord's.
A short rain shower, which interrupted the early part of Middlesex's innings, led to the match becoming a 38-overs-per-side affair.
Malan underpinned the home batting effort with his first hundred of a prolific YB40 season; facing 116 balls and hitting two sixes and nine fours, he took his run tally for the competition to 552 at an average of 78.85.
Eoin Morgan, unusually becalmed as he laboured through 48 balls, was Middlesex's next best scorer with 22 and, at the halfway stage, it seemed as if Gloucestershire, joint top of Group C when the match began with 13 points from their previous nine games, were well in contention.
Steven Finn and James Harris, however, snatched wickets in their opening overs and by the time they had finished their five-over, new-ball spells, Gloucestershire's batsmen were already struggling to keep up with the required rate.
Finn had Hamish Marshall caught at point from the first ball of the innings and Harris snaffled a smart return catch to remove Chris Dent for two.
Much depended on Gloucestershire captain Michael Klinger, whose 46 took his own YB40 run tally to 575 at 95.83, and for a while he was well supported by Ian Cockbain in a stand of 81 for the third wicket.
But Cockbain skied to mid-off, charging at Gareth Berg's medium pace, and Klinger - who had also been dropped on 13 and 19 - was stumped as he went down the pitch to try and heave a ball from left-arm spinner Ravi Patel for six.
Patel then trapped Alex Gidman leg before for 19 and Harris returned to bowl James Fuller for one. Benny Howell straight-drove Toby Roland-Jones for six and swung him for another next ball yet, on 39, his bright effort ended with a skied catch to extra-cover off the impressive Harris, who finished with 3-30.
There were also two wickets for Roland-Jones as Gloucestershire's late order swung with increasing desperation, Gareth Roderick going for 13 and Ed Young 12.
Malan was the only Middlesex batsman to get on top of some disciplined-but-largely-unthreatening Gloucestershire bowling, slow left-armer Young perhaps the pick of the attack with some clever variations of pace.
Paul Stirling went cheaply and, after Joe Denly chipped in with 21, Morgan looked out of touch on a two-paced pitch.
Neil Dexter did manage to increase the scoring rate with 20 from 21 balls, helping Malan to put on a further 58 in eight overs for the fourth wicket, but he mishit to point trying to slash a ball from left-arm seamer David Payne.
Malan celebrated reaching his first YB40 century of the season by swinging Payne for six over deep midwicket and, in the final over of the innings from Fuller, he added a second maximum.