County Championship D1, Hove, day one of four (stumps): Leicestershire 179 v Sussex 137-1
Mushtaq celebrated his milestone with a four-wicket haul
Sussex need 163 runs with nine wickets in hand to win the County Championship title for the first time in their history.
They got the perfect start in their match against Leicestershire after a day of supremacy in the field.
Star bowler Mushtaq Ahmed (4-71) celebrated his 100th wicket of the season as the hosts grabbed three of the six points they need to wrap up the title.
Robin Martin-Jenkins also chipped in three wickets as the visitors crumbled.
Leicestershire started the day well, with opener Darren Maddy scoring 55 and sharing in a 69-run stand for the second wicket with Brad Hodge.
But they lost their last nine wickets for 68 runs as Mushtaq became the first to pass 100 wickets in the Championship since 1998.
Sussex suffered the early loss of Richard Montgomerie, caught behind off Phil DeFreitas for 10.
But Murray Goodwin (71 not out) and Tony Cottey (47 not out) steadied the ship - and Sussex will claim the title, regardless of the result, if they pick up three batting points by scoring 300.
Sussex: R R Montgomerie, M W Goodwin, P A Cottey, C J Adams (Capt)
T R Ambrose, R S C Martin-Jenkins, M J Prior, M J G Davis
Mushtaq Ahmed, J D Lewry, B V Taylor.
Leicestershire: J K Maunders, D L Maddy, B J Hodge, J L Sadler
L J Wright, P A Nixon, G W Walker, P A J DeFreitas (Capt)
J N Snape, V C Drakes, D D Masters.
Umpires: T E Jesty, M J Kitchen.