Ventura took over from sacked Lorenzo D'Anna for just four games, earning one point, and resigned after the 1-1 draw with Bologna.
“If you come here and know that we're bottom of the table with a three-point penalty, you must realise it'll be a battle to the end," Pellissier told Radio Marte.
“What irritated me was that we all worked so hard to understand his style of football, absorb and implement it. His approach was not something we were accustomed to at Chievo, but we tried our best.
“Just as we were starting to get to grips with it, he walks away! That really angered me, because it was like throwing away a whole month."