Jordan Clark claimed a career-best 6 for 21 as Surrey brushed aside the Group 2 leaders for just 92 - before Rory Burns and ex-Hampshire batsman Hashim Amla taking the hosts to 131-1 in reply on a green-tinged pitch.
Burns was on 61 not out and Amla unbeaten on 59 when bad light ended play at 5.09pm, the Test-class pair adding 100 in 30 overs to put Surrey in control of an LV= Insurance County Championship match that began with Hampshire 36 points ahead of their opponents after only three rounds of games.
With 17 fours between them, Burns and Amla - the latter fresh from a pair in the loss to Middlesex - made batting look comfortable against a below-par Hampshire seam attack despite the early loss of Mark Stoneman for seven, thin-edging Kyle Abbott behind.
Clark, consistently finding movement away from the right-handers, had wrecked Hampshire’s in-form batting line-up in cold, overcast conditions.
Kemar Roach and Rikki Clarke also bowled testingly, each taking two wickets, with keeper Ben Foakes finishing with five catches and Clarke three.
All-rounder Clark’s bustling fast-medium proved too hot for Hampshire to handle after he was brought on for the 15th over, with the visitors having battled hard to reach 37 for 1 after being put in.
The 30-year-old struck his first blow in his third over, Sam Northeast (4) slicing to second slip.
Three overs earlier Clarke had removed Tom Alsop for five, thin-edging a beauty to Foakes as he pushed forward.
Hampshire plunged dramatically from 44 for 2 to 44 for 6 as Clark took three wickets in seven balls and Clarke sent back opener Ian Holland, lbw for 22 in the 20th over.
All in all, four batsman fell in the space of 13 deliveries
Clark followed up Northeast’s scalp by having captain James Vince (0) caught behind with the last ball of the same over and then, with the fourth ball of his next over, producing another away-swinger that Liam Dawson (0) edged to second slip.
West Indies fast bowler Roach, who had made Surrey’s initial breakthrough with the new ball when Joe Weatherley (9) nicked to a diving Foakes, returned to have Scott Currie (4) caught behind and at lunch Hampshire were 70 for 7.
The second ball after the interval, a perfect leg-cutter from Clark, saw Abbott (4) edge to second slip and only Lewis McManus, hitting a couple of gorgeous driven fours in an unbeaten 31, resisted as Brad Wheal (5) and Mohammad Abbas, smartly caught low down at first slip by Burns, fell in successive balls to the rampant Clark.
It w as Hampshire’s lowest score against Surrey since they were routed for 91 in Portsmouth 40 years ago – on that occasion they only lost nine wickets as Nick Pocock was absent hurt.
The county’s only lower completed Championship scores of the 21st century were recorded against Essex (76, 2017), Sussex (81, 2001) and Essex again (88, 2019).
Clark said: ‘I’m obviously delighted to get a career-best, and it’s just nice to help to put the team into a position in which we can try to build a big first innings lead.
‘Tomorrow is a big day and if we get a good start in the morning then hopefully we can capitalize with the bat.
‘Today was the day we have been looking for this season, but days like that don’t come around too often.
‘Both Rory and Hashim then batted extremely well. It’s not been plain sailing with the bat but they both showed application and some grit and grind at the crease, which is what we’ve been speaking about in the dressing room.
‘We need to go as big as we can tomorrow.’
Hampshire director of cricket Giles White lamented: ‘It was a difficult day, and not the day we were looking for.
‘We lost the toss, we got stuck in on a pitch where it moved about a bit -and we nicked them! It was a tough day at the office.’