Glamorgan 100 for 3 (Donald 33) beat Middlesex 99 for 8 (Voges 58*, de Lange 3-19, Hogan 3-14) by seven wickets
Glamorgan will play Leicestershire in Cardiff next Wednesday in the quarter-final of the NatWest T20 Blast after topping the South Group and beating Middlesex in Cardiff by seven wickets.
Michael Hogan and Marchant de Lange took three wickets apiece as Glamorgan reduced Middlesex to 99 for 8 in 14 overs in a rain-affected contest, despite a knock of 58 not out from Adam Voges.
Glamorgan won with an over to spare after Aneurin Donald set up the win with 33 from 22 balls. A partnership of 46 between Jacques Rudolph (22 not out) and Chris Cooke (25 not out) saw the Welshmen through to the win.
Play eventually got underway at the apt time of 20.20 after a lengthy rain delay. Glamorgan would have been satisfied with the point to secure a home tie in the quarter-final, but Middlesex, starting the evening in fifth place, a point behind Kent, would have had an anxious wait.
It took just four balls for Glamorgan to claim their first scalp, as Paul Stirling found Michael Hogan at third man off Marchant de Lange. Just five balls later, John Simpson was well caught at mid-on by Jacques Rudolph, who peddled backwards to claim the catch.
Colin Ingram claimed an impressive catch at slip to remove Eoin Morgan from the first delivery of the third over, off de Lange, leaving them 7 for 3. Michael Hogan clean bowled Sean Eskinazi in the fourth over.
After a brief delay, former Glamorgan all-rounder James Franklin was bowled by de Lange in the fifth over, as Middlesex were reduced to 24 for 5. Marchant de Lange took an impressive catch on the midwicket boundary from Craig Meschede's bowling, tossing the ball in-field as he avoided overstepping the boundary.
It wasn't long before Ryan Higgins was on his way, when he drove to Donald at long-on from Graham Wagg's bowling for 16 in the 11th over. Voges, Middlesex's only saving grace, brought up his half-century in the 12th over from 24 balls, having struck seven fours.
Tim Southee struck the biggest six of the innings when he dispatched Graham Wagg to the mid-wicket boundary in the penultimate over. However, Hogan found the batsman's leading edge in the final over, and Wagg duly took the catch.
Former Glamorgan loanee Tom Helm was lucky to survive when Aneurin Donald dropped him three balls later, but he was run out from the final delivery.
Glamorgan started strongly, as Donald struck a couple of boundaries off Helm, and the Welshmen were already more than a quarter of the way to the target after four overs.
Donald was caught by Eoin Morgan off Higgins for 33 before Sowter caught Nick Selman for 16 in the same over and followed up with a second catch to remove the dangerous Colin Ingram off Paul Stirling for three.
The flurry of wickets appeared to slow Glamorgan's scoring, as they still required 31 to win from the final 24 deliveries. Jacques Rudolph glanced a Helm delivery down the legside for four as Glamorgan required 22 runs from 18 balls. They reached the target with an over to spare as Rudolph and Cooke saw them through.