Leicestershire 275 and 139 for 5 (Carson 3-38) need a further 325 to beat Sussex 442 and 296 for 6 dec (Alsop 81*, Hunt 65)
Sussex took four wickets in the final hour to put themselves in a strong position to beat Leicestershire at Hove and consolidate top place in the Vitality County Championship second division.
Offspinner Jack Carson removed Foxes' skipper Lewis Hill, makeshift opener Ian Holland and Lewis Goldsworthy after slow left-armer James Coles had made the breakthrough when he bowled Rishi Patel. Ollie Robinson also claimed the key wicket of Australian Peter Handscomb as four wickets fell for 30 runs in 12 overs.
It left Leicestershire 139 for 5 and still needing 325 in their pursuit of a target of 464 and with the pitch at the 1st Central County Ground showing signs of uneven bounce and occasionally sharp turn for Carson, the hosts will fancy their chances of picking up the five wickets they need on the final day to claim their fourth win of the season.
Foxes' openers Patel and Holland had settled in promisingly with a stand of 51 before Patel upped the tempo by twice hitting Carson over the midwicket boundary. Slow left-armer Coles took over and broke through with his fifth delivery. Patel hit him for a six and four earlier in the over before he was bowled off an inside edge shaping to cut.
Carson returned at the sea end and removed skipper Hill with a beauty which turned just enough out of the rough to find the edge and Holland mistimed a reverse sweep, the ball looping off bat-pad to Ollie Carter at short leg.
Robinson got the wicket he deserved in his eighth over when Handscomb, who had been off the field earlier in the day with a sore shoulder, fended a short ball outside off stump into Carter's waiting hands. Just before the close Goldsworthy was caught at midwicket when he mistimed a slog-sweep to leave Leicestershire facing their first defeat of the season.
Earlier, nightwatchman Sean Hunt scored his maiden first-class fifty as Sussex scored 230 runs in 54 overs before declaring on 296 for 6.
Hunt, who has a career average of just 6.60 and a previous highest score of 22, cashed in after being dropped at slip by Handscomb off Goldsworthy when he'd made just 9. He needed 69 balls to score his first 13 runs but then raced to 50 by smashing 37 off the next 20 deliveries, including two sixes off slow left-armer Goldsworthy over the short leg-side boundary.
Goldsworthy had opened the bowling with offspinner Louis Kimber in an effort to improve Leicestershire's over rate and between them they sent down 21 overs in 55 minutes and 38 in the morning session with Kimber eventually bowling 24 overs unchanged either side of lunch without reward.
Goldsworthy did pick up a wicket when Tom Haines, who'd added 64 for the third wicket with Hunt, chipped back a low return catch and there were two wickets for Scott Currie when Leicestershire reverted to seam. Hunt spliced a pull to mid-off for a fine 65 off 118 balls and Coles, after scoring a run-a-ball 45, holed out trying to deposit Currie over long-off.
Leicestershire employed nine fielders on the boundary after lunch and Tom Alsop took advantage with an unbeaten 81, including three sixes, before Sussex declared shortly before 3pm and left themselves 40 overs and the final day to take ten wickets. By the close they were halfway there.
