كتب : Hatem Maher
The French international bagged his first hat-trick of the season in the first half while Marco Ferrante scored for Ascoli.
The victory maintained Juventus' position on the top of the table with 59 points, 11 points ahead of second-placed Inter Milan who play Lecce later on Sunday.
Trezeguet broke the deadlock in the eighth minute after he controlled Mauro Camoranesi's cross brilliantly on his chest before firing a low shot into the far corner of the net.
The former Monaco striker doubled the lead five minutes later when Alessandro Del Piero fed the ball in the right flank to Camoranesi who sent the ball in the path of Trezeguet for an easy tap-in in the empty net.
Trezeguet completed the rout in the 18th minute as he met Del Piero's low cross with a close range strike past Ascoli keeper.
Ferrante scored the consolation for Ascoli in the 32nd minute after he unleashed a first-timer inside the box past Juve keeper Gianluigi Buffon.
Elsewhere, Roma crushed Livorno 3-0, Chievo thrashed Reggina 4-0, Parma beat Empoli 2-1, Messina edged Cagliari 1-0, Lazio defeated Treviso 1-0 and Udinese were held to a goalless draw with Fiorentina.