Colin Ackermann was unbeaten on 164 as Leicestershire continued to build an impressive first innings score on the third day of their Specsavers county championship match against Sussex at the Fischer County Ground.

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.

Resuming in the morning with the Foxes on 112-2, both Ackermann and Mark Cosgrove were 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, 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 lively partnership of 75 for the fifth wicket before edging a delivery from Wells that bounced more than he expected into the gloves of wicket-keeper Ben Brown.

Leicestershire went in for tea at 329-5.