Match scores (Radlett)
Middlesex beat Glamorgan by 16 runs
Middlesex inns: 243 (48.4/50 overs. Franklin 54, Malan 50, Voges 40; Ingram 4-39, De Lange 3-35, Carlson 1-30)
Glamorgan inns: 227 (48.3/50 overs: Ingram 53, Lloyd 48; Finn 4-39)
Match report
England's Steven Finn produced a high-class display of fast bowling to maintain Middlesex's slim hopes of reaching the knock-out stages of the Royal London One-Day Cup.
The pace bowler took four for 39, including a spell of three wickets in nine balls that proved pivotal in a tight contest.
Set 244 to win after Middlesex were bowled out eight balls shy of their 50 overs, Glamorgan looked well on course for victory at 104 for one.
But Finn intervened and although all-rounder Colin Ingram followed up a four-wicket haul with a run-a-ball fifty, Glamorgan fell 16 runs short.
The match at Radlett was in effect an eliminator with the loser left with little chance of progressing to the quarter-finals.
Between them the two sides had won three matches in 10 attempts in the competition and at times the lack of confidence showed.
But there were also class performances, none more so than those by Finn and Ingram, who took List A best figures of four for 39 with his leg-breaks.
Despite missing Eoin Morgan and Paul Stirling on international duty, given the conditions Middlesex would have been disappointed not to have reached 250.
Opener Dawid Malan scored his first half-century of the season but he became Ingram's first victim when he was bowled trying to cut.
Malan and Adam Voges (40) added 70 in 12 overs after Middlesex had lost Nick Gubbins and Nick Compton cheaply but Malan's dismissal undermined the innings.
With the hosts in danger of coming up well short of a good total, James Franklin played a careful captain's knock to rebuild the innings and received good support from Toby Roland-Jones (22) and Tom Helm (25).
Franklin was dismissed for 54 from 75 balls in the 47th over as Marchant de Lange finished with three for 35.
Glamorgan set off brightly, posting 53 before losing skipper Jacques Rudolph, caught at slip off Finn.
David Lloyd and Will Bragg added a further 51 but just as it seemed the visitors would stroll to victory Finn took three for none in nine balls.
With Roland-Jones chipping in suddenly Glamorgan were 109 for five before Ingram and Chris Cooke dug in. They were two of five South Africans in the visiting side, complementing four Welshmen and two Australians.
The pair had added 65 when Helm bowled Cooke and followed up with the wicket of Craig Meschede two balls later.
As long as Ingram was there Glamorgan had hope but when he skied Ryan Higgins to midwicket there were still 24 runs needed with only one wicket left.
Higgins bowled Michael Hogan in the penultimate over to finish with three for 32 and keep Middlesex in the competition.