Fiorentina coach Vincenzo Italiano was left angry after defeat at Sassuolo.
Sassuolo were again impressive for the 2-1 win, with the victory secured in injury-time. Giacomo Bonaventura was sent off for dissent for the Viola.
Italiano said, “I had assumed there was an extra man in the box because we were down to 10, but looking at it again, we were all paired with the marking and that goal shouldn't have happened.
“I cannot be calm, it's impossible after you concede a goal like that 30 seconds from time and bring home zero points.
"The opening goal could've been avoided too, and it hurts because it is not the first time we've done that."