Lucho Gonzalez says Manchester United underestimated Porto last week.

The midfielder reckons Porto surprised United last Tuesday but does not expect a repeat.

He said: "Carlos Tevez told me it had been more difficult than they thought. We have a slight advantage for the second leg and have to make the most of it.

"We know they have great players and that Cristiano Ronaldo is a big star - but even stars can be beaten."