Nottinghamshire 77 for 1 (Slater 29*, Clarke 1-11) trail Surrey 402 for 6 dec (Borthwick 137, Pope 106) by 325 runs
Nottinghamshire dented Surrey's prospects of rounding off their County Championship campaign with a victory as they saw out a tricky session on the third evening at the Oval.
The home side declared at 402 for 6 and set out to try and capture 20 wickets in the time remaining, but they were largely thwarted by Nottinghamshire, who reached stumps for the loss of Steven Mullaney.
Ben Slater was 29 not out and Ben Compton unbeaten on 16 as they steered the visitors to 77 for 1 before bad light ended play - meaning a draw looks the most likely outcome in this rain-affected climax to the season.
Having lost virtually four entire sessions to poor weather, the pair looked keen to step up the pace once the umpires finally gave them the green light to resume at 248 for 2 soon after 1pm.
Pope, who returned to the crease on 79, lost no time in advancing towards the eighth ton of his first-class career as he square cut Mullaney and Paul Coughlin for boundaries. The 21-year-old reached three figures from 165 balls with a rather more uncertain shot, an outside edge off Jack Blatherwick that flew through the gully area for four.
But Pope did not last much longer, misjudging a delivery from Jake Ball on his leg stump and lofting it to Compton on the midwicket boundary.
Surrey began to lose wickets at a steady rate, with Ben Foakes heaving across the line at Blatherwick and getting a bottom edge that scattered his stumps.
Mullaney, who put in a lengthy stint from the Vauxhall End, picked up two scalps in the run-up to tea, trapping Will Jacks in front of his stumps with an inswinger.
Borthwick - who had earlier been dropped at second slip by Matt Carter - was the next to go, flashing outside off stump at Mullaney and enabling Tom Moores to claim his third dismissal of the innings.
Rikki Clarke and Jordan Clark joined forces for a concerted assault on the Nottinghamshire bowling either side of the interval, putting together an unbroken partnership of 52 from just 10 overs.
Clarke was 36 not out and belted both Coughlin and Mullaney over long on for sixes, while a square cut for four by Clark off Liam Patterson-White raised the total above 400 and triggered an immediate Surrey declaration.
That left Nottinghamshire to face a scheduled 34 overs, but Morne Morkel's opening spell was surprisingly wayward and he was withdrawn after conceding 24 from four overs - including a long hop that Mullaney hooked for six.
By contrast, Clarke beat the outside edge several times and made the initial breakthrough when Mullaney padded up to a straight ball.
However, Slater looked strong off his pads, hitting five boundaries before the darkening sky halted play with 14 overs still to be bowled.