Jose Mourinho has backed his old club Porto to provide the biggest shock of the Champions League quarter-finals by knocking out Manchester United.

"They can eliminate United," said the former Chelsea manager. "Porto are a team with a tradition in the Champions League. It is a team that year after year is participating in the competition. These players have not won anything at European level but they have the experience and the mentality. The structure of the club is strong and they play in the Champions League without fear. So they can eliminate United. It is possible."

Mourinho, whose Internazionale side were beaten by United in the last round, was in charge of Porto in 2004 when they knocked out Sir Alex Ferguson's team over two legs en route to winning the competition. "In 2004 everyone thought it was impossible," Mourinho said, "so why cannot it be possible now too?"

Speaking in Lisbon after being awarded the honoris causa at his old university, Mourinho was also asked about Chelsea's chances and appeared to be critical of his former club. "It is a club with a big economic dimension but with a lack of structure," he said. "The structure of a club should be moulded to the philosophy of their coach, his needs and way of thinking."

Nonetheless Mourinho also described the London club as "a child for me" and backed them to beat Liverpool when the two sides renew hostilities in the Champions League. "They [Chelsea] have a very strong squad. In these type of matches they are even stronger. They have a good mentality. I believe in them."