"Olympiacos is always in my heart!" he told gazetta.gr.
"Olympiacos are having a great year, a good season. They can get past United. It will be a tough rematch in Manchester. I know United well and, although they are not at their best, they are a very experienced team.
"But I back Olympiacos. If they work hard, they have the skill to do it. It would be a great success to achieve qualification."