The West Indian Test all-rounder took 26 off the final over of his side's innings, sent down by the England seamer Andy Caddick, as the visitors posted 169 for 9 from their 50 overs after winning the toss. That might have proved a challenge on a slow pitch, but the home captain Peter Bowler, with 41, and Richard Harden (39) used their experience to guide Somerset home with 6.3 overs to spare.
Graham Rose collected the gold award for his miserly eight-over spell of 2 for 10, during which he dismissed the openers Giles White and Jason Laney with only 19 on the board.
McLean was not even facing when Caddick began the last over of Hampshire's innings, with the visitors struggling on 142 for 9. Kevan James took a single off the first ball and the next five deliveries went for four, six, four, six, six.
All were front-foot shots and with the biggest hit McLean deposited the ball over long on into the nearby churchyard.
Hampshire needed the late boost from McLean after seeing their early batsmen perish to loose shots. Somerset bowled tightly and there were two wickets each for Rose, Mushtaq Ahmed, Marcus Trescothick and Adrian Pierson. They were backed up by some excellent fielding, including a stunning extra-cover catch by the coach Dermot Reeve, who went full length to his right to dismiss Peter Hartley for 20. James was at fault with the run-out of Adrian Aymes for a duck, but redeemed himself with 33 not out after Hampshire had slipped to 95 for 8.
With Somerset's poor early-season batting form, 170 to win was no formality, especially when they lost Mike Burns in the first over from McLean.
However, Bowler dug in and Harden produced some exquisite cuts before being given out lbw to James, despite stretching well forward. At 133 for 5, the outcome was still in the balance, but Keith Parsons saw Somerset home with 32 not out after being caught off a no-ball in the closing stages.
Somerset's victory means they now have five points from four group matches.
Australia are to persist with their policy of having two captains in the run-up to next year's World Cup. Mark Taylor will carry on as the Test skipper with the one-day captain, Steve Waugh, also told to continue after a meeting with Australian Cricket Board officials.Reuse content