Houllier said: "Milan was very unlucky to get injured with a broken ankle last season and that's probably helped as he did not come back until March and it looks as if it made him more fresh than the others.
"He's had his best form in this tournament. He's a very unexpected type of centre forward, he likes to run at defenders, he's strong and powerful with good pace. He's not the finished article but I'm sure he will become greater.
"Just look at his goals record for the national team - he has scored nearly 20 in less than 30 caps."