Alex complained Milan “lack concentration” against smaller sides after a 1-1 draw with Udinese.
The Friulani had gone in front at San Siro before an Mbaye Niang equaliser, but this ends their run of two consecutive victories.
“Clearly we have to do our work, we did fairly well today and it’s a shame we didn’t win,” the defender told Sky Sport Italia.
“In many games against smaller sides we haven’t done well, so evidently we lack a bit of concentration in these matches.
“Next week we have to do better and focus at all times.”
See the latest Serie A predictions and betting tips with Eurotips.co.uk