Hampshire 539 and 171 for 8 dec. (Donald 52) lead Warwickshire 307 (Hain 129*) and 31 for 3 (Abbott 3-18) by 372 runs
Kyle Abbott produced a whirlwind evening spell with the new ball to put Hampshire on course to beat Warwickshire at the Ageas Bowl.
Fast bowler Abbott snatched 3 for 18 in five overs to put his side in the box seat, after Hampshire had set the visitors 404 to win.
The South African accounted for both openers, Dominic Sibley and Will Rhodes, along with nightwatchman Olly Stone in a breathless stint - which left Warwickshire on 31 for 3 at the close.
Earlier, Sam Hain had celebrated his first Specsavers County Championship hundred for three years. Highly rated batsman Hain needed 196 balls to reach the milestone for the first time since July 2016, which also came against Hampshire, before he eventually ended unbeaten on 129.
The previous evening, Gareth Berg had declared the morning session to be vital in Hampshire's hopes of winning this game.
They needed seven Warwickshire first-innings wickets quickly to move the match along and claimed all seven mid-way through the afternoon session, with five coming in a frantic morning session.
Fidel Edwards struck in the 10th over of the day, the fourth with the fresh ball, when Adam Hose was lbw to an in-swinger, before Keith Barker had former teammate Tim Ambrose caught behind.
Berg and Lewis McManus teamed up twice in an over as both Ben Mike and Henry Brookes edged behind. Edwards then unearthed Jeetan Patel's off stump.
The one constant was Hain, who had batted brilliantly with Rob Yates the previous day and continued that form with an intelligent knock.
Stone added a classy 21 before he was run out by Ajinkya Rahane, while attempting a second run off a misfield, before Oliver Hannon-Dalby edged Felix Organ to first slip.
That meant Warwickshire were bowled out for 307, some 232 runs adrift of Hampshire's first-innings total of 539, but the hosts decided against enforcing the follow-on.
Instead, they gave their pace attack a rest and set about adding runs quickly.
It worked for 10 overs as openers Ian Holland and Organ ticked the score to 45 before they were both castled in consecutive balls, delivered by Hannon-Dalby and Jeetan Patel respectively.
Rahane and Rilee Rossouw followed quickly after, both at the hands of Hannon-Dalby, to leave Hampshire on 52 for four, with the lead only up to 284.
But Aneurin Donald replicated his eye-catching first-innings century with a 41-ball half century - which saw a maximum over deep midwicket - during a 71-run stand with Sam Northeast.
Berg was stumped, Lewis McManus, after an entertaining 20, was caught and Barker edged behind before the declaration was made with Hampshire on 171 for 8.
Warwickshire were given a target of 404 to win the match with a minimum of 107 overs left in the game, 11 of which were bowled on a beautifully hot summer's evening.
Abbott needed just 11 balls to find one to nip back into Sibley's off stump. The former Test bowler then had Rhodes caught low at second slip by Rahane and nightwatchman Stone bowled next ball to reach 41 scalps for the season.