A fighting half-century from skipper Tom Abell helped Somerset build a 63-run lead over Hampshire on an eventful opening day at The Ageas Bowl that saw 15 wickets fall.
Abell was unbeaten on 52 - guiding his side to 142-5 - after Hampshire were earlier bowled out for 79 after being put into bat in chilly and cloudy conditions.
Lewis Gregory was the pick of the Somerset attack, taking 4-26, as the hosts were dismissed inside 41 over.
The home side started the day in third place in Group Two - one spot behind Somerset - and did well to only lose the in-form Ian Holland inside the opening hour. Holland departed for four when Gregory found the outside edge and Craig Overton took the catch at slip.
But during the second hour five wickets fell for 16 runs inside 11 overs with Tom Alsop, Sam Northeast, James Vince and Liam Dawson all posting single-figure scores.
Opener Joe Weatherley top-scored for his side with 20 but Gregory mopped up the tail 50 minutes after the lunch having received excellent support from the admirable Overton and Josh Davey who each picked up two wickets.
The overhead conditions continued to favour the seamers in the afternoon session and Somerset fell to 11-2 inside four overs when new-ball pairing Keith Barker and Mohammad Abbas dismissed Tom Lammonby and Eddie Byron cheaply.
Kyle Abbott then trapped James Hildreth lbw for 14 before Abell and Bartlett posted the first 50 partnership of the match following a short rain delay.
The 54-run stand was broken by Abbott who tempted Bartlett, who had played well for his 27, into playing at a rising delivery and Dawson snared a high catch at second slip.
But Abell and Lewis Goldsworthy held firm against some top-class bowling until the penultimate over of the day when Holland beat the defences of Goldsworthy with a full-length ball that clattered into the stumps.
A Craig Overton-inspired put Somerset in control against Hampshire as the visitors dominated the second day at The Ageas Bowl.
Overton - the leading wicket-taker in the LV=County Championship - demonstrated his batting credentials by top-scoring with 74, then starred with the ball as his side opened up a 165-run lead as Hampshire closed on 92-3.
The England paceman hit 10 fours on his way to his 13th first-class 50, before he removed opener Ian Holland, Tom Alsop and nightwatchman Kyle Abbott during a hostile spell of bowling late in the final session.
Alsop and Weatherley had dug in admirably in a 56-run stand before the left-hander fell for 32 five overs from the close.
Overton struck again in the penultimate over of the evening when he trapped Abbot lbw for a duck for his 30th wicket of the campaign.
Weatherley was unbeaten on 31 alongside new batsman Sam Northeast, with the pair to resume their innings at some stage on Saturday with heavy rain forecast in Southampton.
Somerset started the day on 142-5 and added another 47 to their total before skipper Tom Abell's stubborn innings was ended on 62 by a ball that nipped back into the top of his off-stump from Abbott.
Nightwatchman Jack Leach, dropped when on three in the final over of the first day, made the hosts pay for that mistake with an entertaining 34.
But the England spinner perished after trying to lift Keith Barker over the slips cordon only to find the hands of Liam Dawson.
Somerset's deep batting line-up then proved its worth as 143 runs were put on for the last three wickets, spearheaded by Overton.
The giant quick was ably supported by Steve Davies and Lewis Gregory who each scored 33 as Somerset, who sit in second spot in Group Two one spot above Hampshire, built up a handsome 257-run lead after recovering from 36-3 to be 336 all out.
Left-armer Barker was the pick of the home bowlers finishing with 4-67 alongside South African quick Abbott who took three wickets.
Rain and bad light frustrated Somerset's push for victory with just nine-and-a-half overs bowled before play was abandoned after just 45 minutes late on Saturday at The Ageas Bowl.
Hampshire closed the day on 110-4 in their second innings - still trailing Somerset by 147 runs - with opener Joe Weatherley unbeaten on 34 and skipper James Vince five not out.
A heavy overnight downpour in Southampton left the outfield saturated as ground staff worked from 10am to dry off the standing water before play finally got underway at 5.30 with a minimum of 16 overs to be bowled.
Weatherley and Sam Northeast came out to bat in perfect seam bowling conditions, with their side on 92/3, as heavy clouds enveloped the ground and the floodlights on.
The pair did well to survive some testing bowling from Craig Overton and Lewis Gregory as Somerset pushed hard for early wickets.
But it was the excellent Overton who finally made the breakthrough with his fourth wicket of the innings, as Northeast mistimed a push towards mid-wicket and George Bartlett took a stunning one-handed catch at short-leg.
However, the visitors' joy was short-lived as play was abandoned by umpires Graham Lloyd and Alex Wharf due to bad light.
A superb all-round display from Craig Overton inspired Somerset to a comprehensive 10-wicket victory over Hampshire as his side wrapped up a fourth LV= County Championship Group Two win at the Ageas Bowl.
England paceman Overton, who is the top wicket-taker in the country, took 5-66 from a mammoth 40 overs as Hampshire were dismissed for 258 on Sunday, putting himself firmly in contention for selection for next month's Test series against New Zealand.
Overton was also the top scorer in the match with 74 on Friday and finished with overall figures of 7-82, with Josh Davey also playing a significant role in the triumph taking 5-30 on the final day.
The defeat was Hampshire's second successive heavy loss following last week's innings and 289-run humbling by Surrey having started the season strongly by winning two and drawing one of their first three matches.
Although the hosts batted with much more gumption to pass 200 for the first time in four innings, their pitiful day one effort of 79 all out left them with too much do against their in-form opponents.
The visitors looked set to wrap up the win just after lunch when Lewis McManus departed for 17 only for Keith Barker and Felix Organ to frustrate their hosts with a two-hour stay at the crease.
Organ batted with great discipline and determination to score just seven runs from 108 balls before falling to a diving catch by the irrepressible Overton off Davey.
Mohammad Abass was the last man out leaving Barker unbeaten on 52 before Eddie Byrom knocked off the two runs needed for the win with rain beginning to fall and the light fading.
Hampshire started the day trailing by 147 runs after rain washed out all but nine overs on Saturday, and frustrated Somerset for almost an hour with Joe Weatherley and skipper James Vince scoring just 20 runs in the first 13 overs against some tight bowling.
Davey finally got the breakthrough when he found the outside edge of Weatherley's bat and Steve Davies took a sharp catch behind the stumps to end the opener's dogged innings of 44 from 209 balls.
Davey struck again in his next over as Liam Dawson was trapped lbw to pick up only the second pair of his career
It was Overton who grabbed the vital wicket of Vince just after lunch when Davies took another fine catch to dismiss him for 42 which firmly put his side on course to an excellent win ahead of next week's clash with Surrey.