TOM Alsop's maiden Hampshire hundred helped win a Royal London One Day Cup thriller against Surrey at The Ageas Bowl.

The 20 year-old’s 116 (121 balls, ten fours) laid the foundation for Hampshire's 289-8, after losing the toss.

It proved to be just enough as Gareth Berg (4-64) took three wickets in four balls to secure a six-run win against a Surrey side that had needed 11 off the final over.

Alsop, who retired hurt on 83 in his first Royal London One-Day Cup appearance of the season, was composed throughout as he followed his 50 at Bristol by becoming Hampshire's first limited-overs centurion of the season.

Despite seeing six of his more experienced teammates depart he grew in confidence, reverse-sweeping Zafar Ansari for four before reaching his ton from 104 balls.

The left-handed academy product was dropped on 18 by Sam Curran, who with the sun in his eyes failed to land a hand on the ball at mid-off.

But until he was bowled in the 45th over by Tom Curran, he offered no other chances during a fabulous knock that gives Hampshire great hope after a difficult first two months of the season.

Alsop anchored the Hampshire innings like a veteran.

After Jimmy Adams was bowled in the second over, he added 62 in the next ten with James Vince before Hampshire’s captain, having made a 37-ball 41, pulled Ravi Rampaul's seam-up to square leg.

Alsop then put 116 in 21 overs with fellow left-hander Sean Ervine who, having made a second fifty in as many days, was out to the very next ball - as Alsop had been at Bristol the night before.

Hampshire, already without Adam Wheater (sore neck) missed Shahid Afridi from their lower order, their overseas signing having damaged a finger in dropping a catch in the defeat against Gloucestershire 24 hours earlier.

Liam Dawson and Will Smith were both bowled leg stump for seven in successive Gareth Batty overs after Surrey’s captain switched to the Hotel End.  Lewis McManus (16), Gareth Andrew (21) and Gareth Berg (11no), who replaced Ryan Stevenson in the other change to Tuesday night’s team, scored some useful lower-order runs.

Hampshire were restricted to less than 300 in a 50-over innings for the first time this season.

But they performed excellently in the field, against Surrey's formidable batting line-up.

Berg’s athleticism helped him to a low return catch that accounted for Steven Davies in the second over of the reply.

And after a 66-ball stand of 58 between Jason Roy (29) and Kumar Sangakkara (33), Surrey’s dangermen were dismissed in successive overs.

Sangakkara was caught behind in Andrew’s third over and Dawson bowled Roy with a crackerjack delivery .

Ansari was dropped at first slip off Andrew on 0, but Ervine soon made amends.

When Anul Harinath made a hash of an attempted leg-sweep, Ervine ran across to leg slip to take an easy catch.

Ansari, not for the first time, frustrated Hampshire. He shared a fifth-wicket stand of 130 in 23 overs with Ben Foakes (72) before he was bowled for 62 by the excellent Tino Best.

Midway through the next over from the Pavilion End, McManus produced the best moment of an accomplished night behind the stumps, clinically stumping Foakes following a Mason Crane googly.

But the Curran brothers put on 55 in seven overs to keep the game alive. When Sam was caught at short fine leg with two overs left, only 16 were needed, but Best restricted them to five off the penultimate over.

Then Berg ensured Hampshire avenged last week's record T20 defeat at The Oval.

Hampshire bowling: Best 10-0-47-1, Berg 10-0-64-4, Andrew 8-0-46-1, Ervine 3-0-23-0, Dawson 9-0-48-2, Crane 7-0-38-1, Smith 3-0-16-0.