The Giallorossi were 4-0 up this evening, but after Marquinhos was sent off they conceded twice in two minutes for a final 4-2 result.
"Milan are always Milan, so they are technically gifted and caused problems, especially when we went down to 10 men," the Coach told Sky Sport Italia.
"I am happy with the performance, especially the first half. In the second we tried to sit on our lead and we don't know how to do that."
Daniele De Rossi and Miralem Pjanic started together in midfield with Michael Bradley, an unusual trio under Zeman.
"It was a good game in the first half because we pressured them high up the field and were able to go on the counter. In the second half we got pinned back. De Rossi had a decent performance, although after the break he too struggled and was unable to catch his man.
"Pjanic is technically strong and does his job. I choose the line-up that gives me greater certainty to play good football. Bradley and De Rossi are more 'breakers' than Alessandro Florenzi, so I wanted to block Milan. In the second half we allowed Milan to play in midfield and it showed.
"If there were only 11 players in the squad, then it'd be easy. Seeing as there are 24, I try to use those who give me more guarantees for what they can do."