County Championship D1, Hove, day three: Surrey 283 & 260-6; Sussex 271 (close)
Surrey's Ali Brown hit an aggressive 93 not out to set up the prospect of an exciting final day against Sussex at Hove.
The visitors were 260-6 at the close, a lead of 272, despite only 51.5 overs of play being possible.
Surrey resumed on 72-2 and soon lost Mark Butcher, who was caught behind off Robin Martin-Jenkins for 24.
Mark Ramprakash made 51 but skipper Jon Batty (42) joined Brown and helped add 95 for the fifth wicket.
Batty was eventually caught behind off spinner Mark Davis as he tried to seep a ball out of the rough and Rikki Clarke soon became Martin-Jenkins' second victim of the day, lbw as he played across the line.
But Brown could not be dislodged by Sussex and had hit two sixes and 11 fours by the close, which came after partner Marytin Bicknell was struck on the arm by a ball from James Kirtley in fading light.
Sussex: M H Yardy, R R Montgomerie, P A Cottey, M W Goodwin,
C J Adams (Capt), M J Prior (Wkt), R S C Martin-Jenkins, M J G Davis,
Mushtaq Ahmed, R J Kirtley, J D Lewry.
Surrey: S A Newman, R S Clinton, M A Butcher, M R Ramprakash,
J N Batty (Capt, Wkt), A D Brown, R Clarke, T J Murtagh,
M P Bicknell, J Ormond, N D Doshi.