A monumental innings of 160, the highest List A score of his career, by Varun Chopra helped Essex Eagles revive their Royal London Cup campaign against Somerset at Chelmsford.

The 30-year-old’s 149-ball innings lasted from the first delivery of the match to the second ball of the final over, and included nine fours and six sixes. It took his total in the 50-over competition this season to 286 at an average of 71.50.

But Essex’s 40-run victory, ending two successive defeats, was also aided by a surprise five-wicket haul from Shane Snater, the Zimbabwe-born Netherlands seamer, playing only his second game after a successful spell in the 2nd XI. Snater broke two promising partnerships that knocked the stuffing out of the Somerset response, and removed their top four run-scorers. He finished with five for 60.

Chopra shared a 141-run stand for the fourth wicket in 27 overs with Ravi Bopara, who hit 73, and 50 in 28 balls with Ryan ten Doeschate for the fifth wicket. Even so, the Eagles only edged beyond 300 thanks to 98 runs in the last 10 overs after they managed a parlous 42 runs between overs 11 and 24.

In pursuit of 314, Somerset lost two wickets to Neil Wagner inside the first six overs. Steve Davies fell lbw for two and Johann Myburgh, having hit successive boundaries, flashed at one outside offstump and was caught behind.

Peter Trego and James Hildreth settled into a 69-run partnership in 13 overs that righted the Somerset response until three wickets fell in the space of 17 balls.

Snater had bowled a succession of wides and long hops, but had the prized scalp of James Hildreth as his first Essex wicket. Hildreth, who had scored 281 in three previous Royal London games this season, chipped the ball up to Ashar Zaidi at mid-on for 24.

And Snater had a second wicket seven balls later when Trego got a leading edge and lobbed it back to the bowler. Trego, who hooked Wagner for six, had reached his half-century from 49 balls just three deliveries earlier. When he went off after five overs, Snater had two for 37 and had bowled five wides and one no-ball.

The collapse continued when Simon Harmer had the Yorkshire-born Australian Matt Renshaw lbw, and suddenly half the Somerset side had gone for 120 in the 20th over. But 19-year-old Tom Banton posted his highest List A score of 40 in a 65-run stand with Roelof van der Merwe that frustrated Essex for 13 overs.

But the England Under-19 batsman became Snater’s third wicket, when he hammered the ball back to the bowler. Wagner’s return accounted for Craig Overton, who played into Harmer’s hands at midwicket for 12.

Van der Merwe continued to offer resistance and reached a 47-ball fifty with a six off Ashar Zaidi, but then swept Snater high to deep midwicket on 61 where Tom Westley took the catch. Jamie Overton followed when he lofted Bopara to Harmer on the wide mid-on boundary, and Somerset’s second defeat in a row was confirmed when Sam Cook took a catch over his shoulder to give Snater his fifth wicket with 11 balls to go.

Put in, the Essex openers had 33 on the board in six overs when Adam Wheater bounced down the wicket and smashed Craig Overton straight to van der Merwe at cover. The same Overton accounted for Westley for four to a leg before that might have been heading down legside.

When Dan Lawrence chipped up Trego’s slower ball tamely to Hildreth at cover, Essex had lost three key wickets in seven overs for 37 runs.

Chopra took a liking to Jamie Overton, twice pulling him over square leg for six, one flat, the other long and high. One over cost 15. When he reached 34, Chopra passed 4,000 career List A runs. His fifty came out of 84 in 57 balls.

But the runs dried up against Trego and Tim Groenewald. Indeed, there were 44 deliveries between boundaries before Bopara launched Trego over long-on for six. That marked the acceleration point. Bopara’s fifty took 69 balls, and contained one four, that six and a lot of nurdled singles. Chopra reached three figures from 114 balls before Bopara tried to run Groenewald down to third man, but only succeeded in edging behind.

As the innings entered the final 10 overs, the scoring tempo increased dramatically and ten Doeschate helped himself to 10 runs from two balls by van der Merwe, including a six out of the ground. Chopra followed with two maximums over deep extra cover against Groenewald, the second taking him past his previous best of 124. But on 261, ten Doeschate picked out Jamie Overton at deep midwicket for 23 to spark a tumble of six wickets for 52 runs.

Zaidi lofted van der Merwe third ball for six over cow corner, and ramped the next ball for four before departing caught on the rope for a five-ball 11. Chopra’s fifth six sailed over midwicket off Craig Overton before he passed his 150 from 145 balls.

Before then, Harmer holed out in similar fashion to ten Doeschate and Wagner gave Groenewald a third wicket at a personal cost of 43 with a chipped shot straight to Max Waller at mid-off Chopra’s sixth six cleared long-off from the first ball of the last over, but he was finally out next ball, caught just behind square. The innings was wrapped up a ball later when Cook failed to beat Waller’s throw.