Matt Critchley's all-round brilliance hands Gloucestershire their first defeat

Tom Westley continued his late-summer purple patch of run accumulation with a well-crafted 92 to inflict the first defeat of the Metro Bank One-Day Cup campaign on Gloucestershire and enhance Essex's chances of qualifying for the knock-out stages.

The Essex captain has now racked up 443 runs in seven innings in this season's competition, including a century and three fifties. Add in three red-ball centuries in June and July's matches and he has scored 905 runs in just two months. His latest knock encompassed 103 balls and included eight boundaries.

Gloucestershire were already through to the knockout rounds - they wait to see if they are straight into the semi-final as Group A winners - but after six successive wins this was an underwhelming performance against an Essex side who have now won four games in a row. The visitors were dismissed for 159 with 89 balls to spare with Matt Critchley hastening the 130-run defeat with 3-27.

Essex had looked set for a bigger total score while Westley was at the crease. But from 182 for 2 they lost eight wickets in 15 overs, subsiding to 289 all out, to a Gloucestershire spin attack that found turn and grip on a worn Chelmsford wicket. Jack Taylor led the way with his leg breaks for career-best List A figures of 5 for 61.

Like Westley, James Bracey had also been in scintillating form in the competition, with 431 runs from his first six innings. His wicket, heaving across the line against Simon Harmer for 37 at 77 for 4, opened the door for Essex and they duly burst through.

The loss of opening partner Cameron Bancroft, caught behind jamming his bat down to a ball of full length from Jamie Porter, did not inhibit Bracey. He was soon finding gaps in the field and pulled Shane Snater for six over fine leg. However, he contributed to the exit of the becalmed Ollie Price, his drive being deflected on to the stumps by Porter, following through.

Ben Charlesworth lofted Westley for a straight six, but in attempting a second next ball was well held on the boundary. Jack Taylor followed Bracey when he squirted Luc Benkenstein to short third man to reduce Gloucestershire to 88 for 5 before the halfway point.

Graeme van Buuren prodded unconvincingly at Westley and was caught behind and Miles Hammond's careful 30 was undone when he lunged forward and was bowled by Matt Critchley. Three balls later Tommy Boorman was caught behind and the leg-spinner had a third wicket when Zaman Akhtar was caught and bowled.

At the start of the day, Matt Taylor extracted some early life from a green-tinged pitch used for all four of Essex's home 50-over games and got one to go away from Robin Das. Bracey took the catch at full stretch behind the stumps.

Things looked went well for Essex for the next 30 overs or so as Westley put on 103 for the second wicket with Critchley and 75 for the third with Charlie Allison. The innings went downhill once Allison departed.

Critchley had just brought up the century partnership with Westley inside 18 overs with his seventh boundary when Ollie Price got the next ball to turn late and rapped his left pad. He departed for 64 from 66 balls.

Allison's enterprising 40 from 43 balls ended when he sliced to short extra cover off Jack Taylor to precipitate a collapse with three wickets in 23 balls. The Gloucestershire captain quickly accounted for Luc Benkenstein, caught at long-off, and brother Matt had Curtis Campher cross-batting to long leg.

The wickets did not stop there. Westley's 135-minute stay ended when he was bamboozled by one from van Buuren that kept low. Quick hands by Bracey had Simon Fernandes stumped chasing a wide one from Price and Snater perished launching Jack Taylor to long leg

Some belligerent late hitting from Harmer, including two huge sixes off, took him to fifty from 36 balls before he gave a tame return catch to Jack Taylor, who wrapped up the innings by having Charlie Bennett claimed at long-off.