Hampshire were set to concede a first-innings deficit to Surrey despite fifties from Michael Brown and Michael Lumb on day two at the Rose Bowl.
Brown (66) and Lumb (60) rescued the hosts from 13-2 with a stand of 133, before the hosts lost five wickets for 28 runs to put Surrey back in control.
Hampshire battled to 204-7 in reply to Surrey's 278 by the time bad light had brought an early close.
Saqlain Mushtaq was the pick of the Surrey bowlers, taking 2-32.
In cloudy conditions which again favoured the seamers, Hampshire lost out-of-form Jimmy Adams for a duck in only the fourth over of the day, the left-hander nicking a Jimmy Ormond outswinger behind.
Brown and Lumb played sensibly against some probing bowling from Surrey's four-pronged seam attack, but paceman Chris Jordan saw them both off after lunch.
Brown followed a short-of-a-length ball outside off stump and edged the young seamer behind, and Chris Benham could have followed next ball, wicket-keeper Jonathan Batty just failing to take a catch after a top-edged hook.
Jordan did not have to wait long for his second wicket, however, trapping Lumb lbw with a spot of inswing, and Benham was bowled for a single by Saqlain three overs later.
Captain Dimitri Mascarenhas chipped a tame return catch back at Saqlain after making just two and Sean Ervine played on to Collins for 15.
Surrey were therefore restored as strong favourites for a useful lead, despite Ali Brown's failure to hang on to a straightforward chance at backward square when Greg Lamb mis-swept Saqlain on five.
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