Surrey 171 for 4 (Burns 103, Borthwick 50) trail Sussex 415 (Haines 117, Rawlins 65, Wiese 57, Brown 51, Moriarty 5-154) by 244 runs
Rory Burns reached his first hundred of the Covid-shortened 2020 summer but a late break for bad light triggered a dramatic finale to day two as Surrey lost three wickets in three overs and Sussex wrested back control of their Bob Willis Trophy match at the Kia Oval.
Nineteen-year-old off spinner Jack Carson had Burns leg-before for a sparkling 103 with the first ball following a 25-minute interruption, and in the next over 18-year-old paceman Henry Crocombe sent back Jamie Smith and nightwatchman Adam Finch for ducks in successive balls. Smith was bowled, shouldering arms, and Finch pinned leg-before.
Ben Foakes just about dug out Crocombe's hat-trick ball and, with Hashim Amla on 6, Surrey will resume tomorrow on 171 for 4 in reply to Sussex's 415.
But those three wickets for just two runs in fifteen minutes of mayhem has potentially changed the course of the game and Surrey's twilight problems were only brought to an end at 6.10pm when umpires Neil Bainton and Ben Debenham again took the players off for more bad light with 10 overs still technically remaining in the day's allocation.
Before the late drama, Scott Borthwick had made a circumspect 50, from 121 balls, as he and Burns added 164 for the first wicket until the former Durham left-hander was leg-before to Carson, who with fellow teenager Crocombe were by far the pick of Sussex's attack.
Having reached 37 not out in 21 overs before tea, Burns led an impressive acceleration in the final session to show that rapid scoring could indeed be achieved despite a slow and soporific surface.
His hundred, in his first red-ball innings for Surrey this season, took 111 balls and the England Test opener struck 15 fours. He and Borthwick added 108 in 18.3 overs after tea, before Carson parted them.
It was Burns' 19th first-class century, two of which have come for England, and - back captaining Surrey in this match - he was clearly determined to take the match by the scruff of its neck after two months largely spent playing six Tests from inside England's bio-secure bubble.
The left-hander was also no doubt hungry for runs. Burns scored only 20 runs in four innings during the Pakistan Test series, although he did make 57 and 90 in the third Test against West Indies at Old Trafford at the end of July and 234 runs from five innings in that earlier series.
Here, his hard-won Test stature was fully evident as he used his feet to the spinners and also effortlessly outscored Borthwick after safely negotiating a testing new ball spell of 5-2-6-0 from Crocombe - who almost yorked Borthwick with one eye-catching delivery - and then an initial, pre-tea spell of six overs from Carson that cost just four runs.
Burns' one false stroke was a top-edged hook at a George Garton bouncer which flew high over keeper Ben Brown for four to take him to 77, but he was prolific off his pads and quick on anything short.
Earlier, only late hitting from David Wiese and No 10 Carson had managed to haul Sussex's run rate above three per over after they began day two on 239 for 3.
Wiese's 47-ball 57 also made sure Sussex banked four batting bonus points and featured three sixes and six fours - the best of those strikes an almost contemptuous checked straight drive off Dan Moriarty's left-arm spin which brought the former South Africa all-rounder his first six.
And Carson contributed two lusty legside sixes off Moriarty in his 21 before being last out, caught at deep mid wicket with just nine balls of the 120-over first innings limit remaining.
Moriarty, although expensive, took the last three Sussex wickets - with Wiese, taken in the deep and Stuart Meaker, bowled for 12 having a mow from down the pitch, also falling to him after lunch - to finish with 5 for 154.
Off spinner Amar Virdi's 3 for 80 from 32 overs was a worthy effort, and fast bowler James Taylor impressed in a second new ball spell of 2 for 21 in which he removed 16-year-old James Coles, Sussex's youngest first-class debutant, for 11 and Sussex captain Brown for a well-made 51.
Brown, who hit seven fours after resuming on 9, was caught behind off a Taylor leg-cutter after providing most of Sussex's forward momentum following the early loss of first day century-maker Tom Haines, leg-before to Virdi for 117.
Moriarty skidded one out of the footholds into Garton's pads to have him lbw for 12 as lunch approached, but at least Wiese and Carson hit out productively in a ninth wicket alliance of 53 in little more than six overs.