Sussex 438 for 8 dec and 11 for 0 lead Leicestershire 422 for 9 dec (Ackerman 186, Cosgrove 64, Wells 4-81) by 27 runs
Colin Ackermann hit 186 as Leicestershire ended the third day of their Specsavers county championship on close to level terms against opponents Sussex.
The South African, who had been 61 not out overnight, went to his 150 shortly before tea, having faced 294 balls and hit 20 fours.
Having resumed with the Foxes 11 for 2, the first hour of play saw Ackermann and Mark Cosgrove being made to work hard for their runs by fast bowler Ishant Sharma.
The India international, with the wickets of Leicestershire openers Paul Horton and Michael Carberry already to his name, ran in hard from the Bennett End, but other than a very occasional variation in bounce, found little encouragement in the dry but flat pitch.
Ackermann cover drove David Wiese to the boundary to bring up his hundred, and Cosgrove was looking in good shape to follow him to three figures when, on 64, he mistimed a drive at the part-time leg-spin of Luke Wells, giving the bowler a low return catch.
Ateeq Javid, making his debut for Leicestershire, made a laboured 13 off 66 balls before being dismissed leg before wicket by David Wiese, but Neil Dexter joined his compatriot Ackermann in a partnership of 75 for the fifth wicket before edging a delivery from Wells that bounced more than he expected to wicket-keeper Ben Brown.
Lewis Hill, having taken a couple of steps down the wicket, may have been unfortunate to be given out leg before to Wells, before the tiring Ackermann attempted to reverse sweep Wells and top-edged a simple catch to Harry Finch at slip. He had batted for over seven hours, faced 350 balls, and was only one run short of his previous first-class career best.
Ben Raine hit two sixes in a brisk 40 before Leicestershire captain Michael Carberry declared, giving his bowlers six overs at Sussex openers Wells and Phil Salt - overs they negotiated safely.