Acting Middlesex captain Eoin Morgan hit a season's best 90 to inspire his side to a four-wicket Yorkshire Bank 40 win over Leicestershire at Lord's.
Although neither side could progress from Group C, Morgan gave the home crowd something to cheer about by hitting eight fours and four sixes as Middlesex chased down their opponents' 274-8 with 10 balls to spare.
The chase did not began well, however, Dawid Malan (0) and Paul Stirling (15) both being sent back to the pavilion within the first five overs.
The experienced third-wicket pairing of Joe Denly (36) and Morgan regrouped with a partnership worth 72 inside 11 overs that came to a surprise end when the former chipped a return catch to James Sykes.
Morgan reached a 43-ball 50 - his first in all forms of cricket in a hugely disappointing domestic season - by chipping six into the Tavern Stand against Josh Cobb.
He was just 10 short of a morale-boosting century ahead of England's limited overs series with Australia when a mistimed slog sweep against Shiv Thakor flew to Greg Smith at long-on.
Morgan helped add 81 in 10.3 overs for the fourth wicket with Adam Voges during a breezy 63-ball stay, but Voges (37) blotted his copybook by holing out to the same fielder to make it 197-5.
Needing 77 from their final 10 overs, Middlesex added 60 in 44 balls through debutant Ollie Wilkin (20) and John Simpson, with the latter completing the job with an unbeaten 58 from 39 balls.
Leicestershire had earlier lost lost Cobb for six early on, but fellow opener Smith moved smoothly to a 61-ball half-century with four fours and two sixes before being removed by Ravi Patel.
That left Ned Eckersley to be joined by left-hander Matthew Boyce, who took advantage of a short boundary on the Tavern side by twice depositing short deliveries from Patel directly into the Mound Stand.
Eckersley reached 73 before pulling a shot high to Toby Roland-Jones at mid-on, while Boyce (53) was dismissed by rookie seamer Wilkin.
The visitors lost three wickets in 11 in six balls in the quest for late runs, although Tom Wells bucked that trend with 31 off 11 balls.