Kyle Abbott's three-wicket haul helped dismiss Somerset for 216 before half-centuries from captain Sam Northeast, Aneurin Donald and Aiden Markram ensured Hampshire eased to their seventh win in eight games with 18.3 overs remaining.
A home semi-final awaits... 👀 pic.twitter.com/IWIM3Z2NHL
— Hampshire Cricket (@hantscricket) May 5, 2019
Somerset now face a battle with three other counties – Middlesex, Sussex and Gloucestershire – for the remaining two South Group play-off places when the final round of games is played on Tuesday.
Middlesex are best placed of that quartet to progress following a five-wicket win against Glamorgan.
The competition's leading wicket-taker Nathan Sowter claimed four for 58, to take the leg-spinner's tally to 22 wickets, as Glamorgan were dismissed for 285.
Captain Stevie Eskinazi steered Middlesex to their target with an unbeaten 67 after Sam Robson and Nick Gubbins hit half-centuries to edge them two points clear of the chasing pack.
Benny Howell took a hat-trick as Gloucestershire moved level on points with Somerset and Sussex thanks to a thumping 116-run win over the Sharks at Eastbourne.
Howell claimed the final three wickets of the match to secure a Gloucestershire victory that had been set up with the bat when they piled up 335 for six.
Opener Miles Hammond struck 95 before Jack Taylor made full use of the short boundaries at The Saffrons with an unbeaten 69 off 26 balls.
Daniel Bell-Drummond hit an unbeaten 120 and claimed two wickets as Kent defeated Essex by six wickets at Beckenham.