Sam Cook torpedoes Middlesex after Dan Lawrence, Tom Westley set up Essex

Sam Cook's stunning triple-wicket maiden kept Essex in the hunt for a Vitality Blast quarter-final berth as they beat Middlesex by 21 runs at Lord's.

Seamer Cook ripped the heart out of Middlesex's top order with the wickets of Max Holden, Joe Cracknell and wicketkeeper John Simpson en route to figures of 3 for 23. Aaron Beard (2 for 22) and Simon Harmer (2 for 26) provided great support as the hosts capitulated to 140 for 8 chasing a victory target of 162, only Steve Eskinazi and Jack Davies putting up prolonged resistance.

Earlier, Dan Lawrence, who top-scored with 51, and Tom Westley set a new record for the fifth wicket against Middlesex with their stand of 84, eclipsing that of 63 by Paul Grayson and Andy Flower back in 2003 as the visitors reached 161 for 6 despite 3 for 16 from Chris Green.

Toby Greatwood, on his Lord's debut, made an early breakthrough for Middlesex when Feroze Khushi nicked him to Simpson, and after threatening to cut loose Adam Rossington was pinned in front by Jason Behrendorf.

The in-form Michael Pepper flowered briefly, hoisting Thilan Walallawita's first ball into the Mound Stand, but fell trying to repeat the shot, and when Paul Walter also holed out in the deep off the impressive Green Essex were 67 for 4.

Lawrence and Westley rebuilt, the former taking heavy toll of the wayward Martin Andersson before lofting Walallawita for six as he reached 50 in 32 balls. Westley's 50 was scratchier and saw him given three lives. Simpson failed to stump him on 22, while Greatwood grassed a chance on 33, both off the luckless Luke Hollman, and Holden shelled a third opportunity when Westley had 48. Fortunately for the hosts, neither half-centurion could kick on and only 11 runs came from the final three overs.

If their total looked a little light, Cook's momentous over soon made it look much larger. Holden edged Cook's first ball and though Rossington fumbled the chance, Harmer grabbed the rebound at slip. Cracknell lasted two balls before lobbing back the gentlest of caught-and-bowled chances and the final ball saw Simpson brilliantly caught at second slip by Lawrence to leave the hosts in tatters at 9 for 3.

Jack Davies hit Harmer into the Edrich Stand as he and Eskinazi attempted a salvage operation, raising a 50 partnership off 41 balls. When Cook returned Eskinazi struck him for six over point, but the run rate required kept climbing and scoreboard pressure told when Eskinazi slapped one from Aaron Beard straight to Cook at cover to end the stand at 86.

Davies was caught in the deep in the next over and despite some late six-hitting from Behrendorf Essex won with relative comfort as Middlesex suffered an eight defeat in nine in the competition.