Former AC Milan coach Arrigo Sacchi says the Serie A side's Champions League tie against Barcelona will be 'very difficult' to win.
But the 66-year-old believes Massimiliano Allegri's men could cause an upset if Barca are not at their best.
"Watch out for Milan because they have a lot of international experience. If Barca are at their best it will be very difficult for Milan to qualify, but if they are not then Milan can win," Sacchi said.
"Barcelona are on another level now, but Milan cannot be underestimated."
The former Real Madrid director of football spoke about the return of Bojan to Camp Nou, with the 22-year-old set to face his old side for the first time since leaving them in 2011.
"Bojan is playing pretty well," Sacchi said. "He doesn't always play but he is improving in Italy."
Sacchi also touched on Barcelona coach Tito Vilanova, who has suffered a relapse of a tumour he first suffered with last year.
"When I found out about Vilanova's relapse it hurt me a lot. I am convinced that he will fight it with everything," he said.