Milanic was 45 minutes away from registering his first win as Leeds manager after Mirco Antenucci fired the visitors into a slender half-time lead.
"We scored the goal we had some good counter-attacks, but in the last few minutes of the first half they began with long balls and crosses from all areas," he told Sky Sports News.
"They made a lot of pressure and although we were prepared for it in the second half we made two mistakes and they scored.
"We had some problem in midfield from the pressure from them, but we made some good moves in the second half and their goalkeeper made some good saves."
The defeat leaves Milanic's side 14th in the Championship table and without a win in any of their last four outings.