United defeated Barca in the 2008 semifinals before losing in the final to the Spanish giants in 2009.
"It is the same Barcelona team from 2008 and what I saw for 180 minutes then was the highest level of concentration I have ever witnessed from a Manchester United team in 15 years of being here," said the former England full-back.
"It was unbelievable. The concentration they applied to get that result by keeping two clean sheets over the two legs was phenomenal.
"If any of them want to understand how to beat Barcelona, they only need to watch those two matches again.
"This time it is easier. They only have to do it for 90 minutes.
"If they repeat that same level of intensity, concentration and discipline to stick to the task, as they did on those two nights, the challenge is there for them to go and make history and win the European Cup."