Milan will have to wait until the next matchday to qualify for the Europa League knockout stages, having failed to beat AEK a second time on Thuesday, but Montolivo felt his side were not ruthless enough in their approach.
“After a long time out, I lacked a bit of confidence, but I’m quite happy [with myself] now,” the midfielder told Milan TV.
“I’m sorry for the first half, we weren’t at our usual levels, we lacked character and struggled to keep the ball.
“We improved after the break and deserved a goal, but we still have to do more. Sunday becomes an important game for us.
“We need to grow in terms of character, play less long balls, play more balls on the deck and play at a quicker tempo.
“In terms of playing without fear, we didn’t in the first half, which made things a lot easier for AEK. We have to improve a lot.
“We lack the character and conviction needed to win ugly. We can’t always win deservedly. We also need to win by being ugly and even lucky.”