Brocchi had won 1-0 at Sampdoria on his debut after replacing Sinisa Mihajlovic, but was jeered off the field at San Siro.
“I didn't expect a different game as such, as I knew Carpi were good at closing down the spaces and putting up a wall," Brocchi told Sky Sport Italia.
“The team tried to play and move the ball, I think we had about 75-80 per cent possession. That might not mean quality of football as such, but we did take control of the match.
“I think what we lacked this evening was the finishing. We put balls into the box and tried to create chances, but were missing some of the determination to finish them off.
“I always ask the strikers to seek each other out and help each other. Unfortunately today they were close by, but only shook off markers trying to get the ball to feet.
“It is a step backwards from our performance against Sampdoria because we didn't win. This Milan has to win. We needed a different level of determination and sporting passion. We didn't attack the box enough.
“I have some very good strikers and we need to make them move in a way that is useful to the team. I am happy with the strikers I have, but not with the way they interpret certain situations.
“I never thought this was going to be a simple job, but at the same time nothing is easy. We just have to work, try to emerge from certain situations and identify the problems we saw tonight.
“In my 10 days at the club, there have been only three real days of training. We won't have much time afterwards either, as we have to play again on Monday."