The Italian defender has come under fire from the Ibrox supporters following a series of indifferent performances. But Advocaat believes the criticism of the player is unjustified, and insists he will not be relinquishing the captain's armband.
"There is no dilemma with Amoruso," the Dutchman said. "I made my choice for him to be captain and when I have made up my mind I don't change it.
"I think the way he plays has nothing to do with his captaincy. Remember, too, that I made him captain - he didn't do it by himself. I thought the fans' reaction to him against Dundee United on Saturday was quite unfair. If players can do the job, they stay, if not, I find someone else. But, so far, he has shown he can do it."
Rangers go into tonight's match aiming to build on a marvellous 2-1 victory in Germany a fortnight ago and book their place in the third round. With Celtic falling by the wayside on Tuesday in Zurich, the Premier League leaders are Scotland's last representatives in Europe. They are expecting a 50,000-plus crowd, and Advocaat is quietly confident they can go through.
"It was an important result for the club in Leverkusen, but also for Scottish football because everyone in Europe was talking about it," he said. "We always try to play our own game. We are facing a good team, but we always try to play our own system in any match.
"There are several examples of teams with away wins losing, like Aston Villa, so we know we still have it all to do."
Their Finnish international striker, Jonatan Johannson, has recovered for a groin strain and is expected to regain his place in the starting line-up ahead of Argentina's Gabriel Amato. But Gordon Durie is again ruled out with an achilles injury while Daniel Prodan, who has yet to make his debut for Rangers, faces a knee operation in Antwerp on Monday.