Worcestershire 40 for 2 trail Hampshire 290 (Vince 75, Berg 75*, Leach 4-42) by 250 runs
James Vince put a disappointing winter behind him to start the season with a glorious half century as Hampshire held a slight first day advantage over Worcestershire.
Stylish batsman Vince scored 346 runs for England in six Tests during tours of Australia and New Zealand, to leave his international career in limbo.
Early season Specsavers County Championship runs were predicted to be key to whether he would cement his spot in England's top order, and he replied with a stylish 75.
Hampshire were unsurprisingly asked to bat by Worcestershire captain Joe Leach in an uncontested toss, with a typical April green top wicket and thick grey clouds ready to assist the seamers.
And the decision was almost immediately vindicated as Leach found the edge of a dangling defending Lewis McManus to be caught behind by Ben Cox.
Vince then arrived at the crease and every array of the drive was pulled out in a well-rehearsed Vince textbook, with his half century plundered off a spritely 49-balls.
Other than the odd play-and-miss, Vince offered no chances and never looked in danger of nicking to the slip cordon - a feature which was heavily criticised and analysed during his Test stints.
Jimmy Adams, fresh on the back of an unbeaten 182 in the MCCU match against Cardiff, steadily accompanied Vince with an unflashy 33.
But having celebrated an 106-run stand, Adams was deceived by a Steve Magoffin leg-cutter and was struck on the pads without playing a shot - the bowler's first scalp for the county since re-joining from Sussex this winter.
Vince, having brilliantly taken his boundary tally to 14, was then bowled by Magoffin four overs later.
During the steadfast stand between Vince and Adams conditions appeared to have eased, but after lunch Leach proved the ball nipping around dangerously.
Leach was the main protagonist with his accurate quick bowling, as he beat debutant Sam Northeast for pace - the former Kent skipper driving unconvincingly for 17. Rilee Rossouw followed in a similar fashion four overs later for a 10-ball duck, again Leach clattering into the stumps.
Overseas star Hashim Amla battled the conditions for a gutsy 36 before he was lbw to Josh Tongue and then medium pacer Daryl Mitchell then produced two wickets in as many balls to bowl Dawson, and then pin Kyle Abbott leg before.
When Josh Tongue hit Brad Wheal on the pads, the Hampshire innings appeared to be petering out, but an outstanding unbeaten 75 from Gareth Berg handed the hosts the impetus.
Berg crashed two sixes in a partnership of 48 for the last wicket - with his own fifty coming from 69 balls.
Fidel Edwards was the last wicket to fall, caught behind to give Leach figures of four for 42 along with his 250th first-class scalp - leaving the visitors 18 overs to fend off. But the West Indian needed just four balls to make inroads into the Worcestershire batting line-up - as Brett D'Oliveira looped a simple catch to Vince at mid-off.
Kyle Abbott castled Tom Fell, with three overs left in the day, to leave the visitors 40 for 2 overnight.