'The arrival of Carlos is a double-edged sword,' he said in the Sunday Mirror. 'I am happy for him, but, because he has gone to a rival club, I am worried about him because he can do great things.
'Carlos is an explosive forward and is able to unbalance any defence. He is a big danger to everyone in this league.
'United have some great attacking players with Carlos, Wayne Rooney and Cristiano Ronaldo. They are all quick, fast and will get a strong understanding between them.'