Dawid Malan's century helped Middlesex record a 54-run victory under the Duckworth/Lewis method over Group A rivals Essex at Lord's.
Malan made an impressive 134 from 108 deliveries out of a total of 288 all out after he had lost fellow opener Joe Denly without a run on the board.
He hit four successive deliveries from Essex paceman Maurice Chambers to the boundary on his way to reaching three figures from 89 balls.
The 24-year-old combined with Gareth Berg to add 132 in 20 overs before the latter edged a ball from Ravi Bopara, having struck 61 from 58 balls, to give wicketkeeper James Foster one of his three catches behind the stumps.
However Bopara - given the opportunity by the England and Wales Cricket Board to play in the hope of rediscovering his form after a recent period of absence from the game for personal reasons - failed with the bat.
The right-hander made just two before becoming one of three victims for 20- year-old debutant Gurjit Sandhu as the Eagles slumped to 51-3.
Their hopes were boosted by a fourth-wicket partnership of 102 in 16 overs involving Tom Westley and Owais Shah who both completed half-centuries.
The in-form Westley hit 68, his third 50 in his last five innings in the competition, while Shah returned to his former stomping ground with 53.
Yet just when Essex seemed to have hope the two well-set batsmen were dismissed in successive Paul Stirling overs as the light began to fade.
The gloomy conditions eventually brought about a premature end with 29 balls remaining when umpires Rob Bailey and Steve Garratt called off proceedings with Essex 198-7.