Hampshire 290 (Vince 75, Berg 75*, Leach 4-42) and 163 for 8 (Leach 3-34) lead Worcestershire 211 (Cox 65, Barnard 40) by 242 runs
Worcestershire's Ben Cox claimed a 22nd career first-class fifty as promoted Worcestershire refused to yield, but Hampshire boast a sizeable 242-run lead with two wickets intact following an enthralling second day at the Ageas Bowl in the Specsavers County Championship
Cox collected 65 in a quality-filled knock, as the visitors posted 211 in reply to Hampshire 290, a first innings deficit of 79.
Hampshire then ended play on 163 for 8, with a lead of 242, after a spritely evening of bowling from Worcestershire under clear blue skies.
The hosts began their second innings with gusto as they reach 47 without loss - with Jimmy Adams dropped first ball at third slip the only bump.
But three wickets in four balls turned the momentum around.
Lewis McManus was caught behind off Josh Tongue, while attempting to take his bat inside the line, before Adams was leg before to the first ball of Joe Leach's over.
Debutant Sam Northeast temporarily slowed the wicket taking with a supreme straight drive but was clean bowled by a Leach jaffa next delivery.
James Vince, impressive in the first innings with 75, fell to Steve Magoffin for a second time in the match when he nicked to Daryl Mitchell at second slip.
South African pair Hashim Amla and Rilee Rossouw combined to recover with a brisk 40 run partnership - before the overly aggressive Rossouw was bowled by Magoffin.
Liam Dawson and Gareth Berg both fell soon after each other, both leg before, to Leach and Tongue respectively and then Hashim Amla was run out for a promising 36.
Earlier with conditions starting under grey skies, Nightwatchman Tongue departed to the seventh ball of the day, as he prodded Kyle Abbott to Rossouw at second slip.
Mitchell was handed two lives as he was dropped twice, on 18 and 21, by McManus off Abbott, both tricky chances off either side of the bat.
But Mitchell's luck ran out shortly after when he swiped a wide Fidel Edwards delivery to a juggling Northeast at gully.
Gareth Berg had been the pick of a strong attack in the morning, and found himself in the wickets when Travis Head loosely drove to Northeast, now position at fourth slip, before he bowled Joe Clarke.
With Worcestershire 68 for six, Hampshire would have been expecting a more hefty lead but Cox, firstly with George Rhodes and then Ed Barnard had other ideas.
Like Vince on the opening day, Cox appeared to be batting somewhere else and found run scoring easier than the rest of his teammates.
The wicket-keeper batsman brought up his half century off 58 balls.
Cox added 44 with Rhodes, before the latter was lbw to Abbott, and then 80 in a vital eighth wicket stand with Barnard.
He was eventually dismissed as Brad Wheal went short, pulling straight to Adams at square leg, as Leach fell for a similar trap on the mid-wicket boundary.
Barnard, after a well-made 40, was the last to depart when he slog swept Dawson to Wheal at deep mid-wicket. Worcestershire were still in the match - but only just.