Tom Westley's hard-hitting 93  from 98 balls helped set up Essex's 25-run victory in their first Royal London One-Day Cup match of the season.

Westley shared partnerships of 103 with Alastair Cook for the second wicket and 60 with Varun Chopra for the third against Hampshire at Chelmsford.

But the hosts were pegged back mid-innings and were grateful to Ashar Zaidi's entertaining unbeaten 40-ball 72, which included four sixes, for seeing them to 304 for seven.

Behind the run-rate throughout, Hampshire were always in the game while James Vince (68) and George Bailey (67) were at the wicket - they shared in a stand of 91 for the third wicket.

However, once they had been separated the challenge fell away and the county could not repeat their opening cup win over Kent at Canterbury last Thursday.

Yet the hosts, put in by Hampshire, did not start well. Third ball, Nick Browne was bowled by an inswinger from Reece Topley.

It proved costly as Cook and Westley went on the offensive. The 50 came up in the ninth over and Westley's half-century, off 45 balls, contained eight fours.

The partnership reached 100 in the 18th over but three runs later Cook departed when he completely missed a delivery from Liam Dawson. He had hit 39 from 47 balls.

Chopra had reached 26 when he was caught by a tumbling Lewis McManus and five balls later Westley's bludgeoning innings was over when he was caught magnificently at midwicket by Bailey off Dawson.

Ravi Bopara was the fifth man out, lbw to Mason Crane for 10, before Ryan ten Doeschate was run out scampering a quick single off and not beating Crane's throw.

Adam Wheater and Zaidi improvised well in a stand of 42 for the seventh wicket but then Wheater played across a delivery from Sean Ervine and lost his leg stump to depart for 30.

It was left to Zaidi to take Essex over 300 with a spectacular exhibition of swashbuckling batting.

The Pakistani cleared the catering tent at midwicket off Ervine for a second six and reached a 30-ball half-century with an unorthodox third maximum over third man. He added a fourth straight off Kyle Abbott, and also included seven fours in his 72.

Hampshire's chase started poorly. Michael Carberry was bowled off an inside edge - his second first-over dismissal in successive innings - and the visitors had only progressed to 36 in the eighth over when Tom Alsop lost his middle stump to a swinging Matt Quinn delivery.

Vince and Bailey then teamed up, with the former's half-century coming up from 56 balls at the same time as the 50 partnership.

The stand was eventually broken when Vince gave a return catch to Bopara but Bailey went to his half-century from 47 balls.

Dawson gave support in a 55-run partnership before he was run out by Browne - and next ball Neil Wagner had Bailey caught behind.

Hampshire needed 87 off 66 balls, 79 off 53 and 63 off 42, then Ervine hit Quinn over midwicket for a six that brought up the 50-stand with McManus.

But Ervine, the non-striker, was caught out of his ground shortly after by ten Doeschate to make it 242 for six.

The Essex captain then claimed Gareth Berg to a caught-and-bowled and McManus to a catch on the long-leg boundary.

Wagner wrapped things up with two wickets in two balls, having Abbott caught at long leg and Crane bowled to finish with four wickets for 41 runs.