Somerset surged to the top of the Pro40 League thanks to some highly encouraging performances from their youngsters.

The Sabres leapfrogged Sussex to gain a measure of revenge for their Twenty20 Cup final thrashing 48 hours earlier.

Defending a lower than average Taunton total of 238-5, Max Waller and Mark Turner shone with the ball, while wicketkeeper Craig Kieswetter pulled off two particularly fine dismissals to follow up his 45 with the bat.

Ed Joyce's terrific 94 kept the Sharks in the hunt but James Hildreth made two great catches as Somerset held their nerve to dismiss the visitors for 189 to win by 49 runs.

Somerset had surprisingly chosen to hand left-arm spinner Arul Suppiah the new ball for the first time and he responded with wickets in successive deliveries in his second over.

First Rory Hamilton-Brown swatted him for six and then clipped the next ball to mid-on for 13 before a quicker delivery pinned Luke Wright leg before wicket.

Joyce and Murray Goodwin then added 42 in five overs until Kieswetter superbly held on to a fine edge standing up to the pace of Ben Phillips to remove the latter for 19.

Next ball, Michael Yardy over-balanced as he failed to leg-glance a wide from Phillips and Kieswetter whipped the bails off almost instantly. The TV umpire sent the left-hander on his way.

At this stage Sussex were still well ahead of the required run-rate but the fifth wicket fell when Hildreth brilliantly held on to a full-blooded cover drive from Dwayne Smith off Turner.

And with Waller belying his 21 years to purvey some teasing wrist-spin, Somerset began to take a grip that tightened when Chris Nash advanced inside a leg break and was stumped for 16 before Andrew Hodd edged behind for 17.

A stand of 32 in four overs between Yasir Arafat and Joyce threatened to swing the game back Sussex's way. But Hildreth's second great catch – a stunning, running take above his head at mid-on – removed the latter for 12.

Will Beer holed out on the leg-side for seven and it was all over when Joyce lifted Charl Willoughby to Waller at long-on.

Langer had chosen to field first under lights on Saturday, but last night he opted to bat after winning the toss.

Kieswetter and Marcus Trescothick put on 69 in 10 overs for the first wicket before both holed out to mid-on off Wright. First Trescothick mishit his slower ball for 36 from 30 balls before Kieswetter picked out the fielder for 45.

Number three Hildreth failed to match their rate of scoring but still accumulated well for 45 until he failed to hit Hamilton-Brown's off-spin over long-off.

Zander de Bruyn thumped three cleanly-hit sixes in his 73 from 68 deliveries, but he fell for his ninth score of 70 or more in one-day cricket this season when he was yorked by Arafat.

With overs running out, Pete Trego was rightly promoted above Langer but even the free-scoring all-rounder could make only a run-a-ball 23 with one six until he fell in similar fashion.

The two teams begin a Championship match at Taunton tomorrow morning.