Parma pile the misery on Sassuolo
Cassano set up goals for Raffaele Palladino and Aleandro Rosi in the 32nd and 70th minutes, respectively, before finding the target himself in the 76th.
Sassuolo's Domenico Berardi temporarily made it 1-1 with a penalty in first-half added time after Parma goalkeeper Antonio Mirante was sent off for fouling Berardi.
Sassuolo also ended with 10 men after Francesco Magnanelli picked up his second yellow card in the 88th.
Parma moved into a tie for eighth with Atalanta, 12 points behind Italian league leader Roma. Sassuolo remained last with just two points from seven matches.