Mourinho, who guided Real to the league title last term ending bitter rivals Barcelona's strangle-hold on the trophy, was quoted as saying by the A Bola sports daily: "Portugal don't depend on other teams. They only depend on themselves.
"If they do their job against the Netherlands, they will be in the quarter-final. I think that Portugal are one of the two or three best sides in the competition," he said. "But that doesn't mean much: everything is decided in 90 minutes, extra-time or penalties," the self-styled "Special One" said. "If Portugal get to the quarter-finals, anything can happen."
Paulo Bento's side, who were beaten 1-0 by Germany in their opening match, fought back to win 3-2 against Denmark on Wednesday. They play the Netherlands on Sunday evening in Kharkiv, also Ukraine.
Portugal have three points, as have Denmark, while Germany lead the group with six. The Dutch have yet to get off the mark.