Having sampled the Nou Camp ambience on Wednesday evening, Owen Hargreaves has called on Old Trafford to show the Catalans a 'proper' European atmosphere in next week's return leg.

Almost 100,000 fans crammed inside Barcelona's stadium for the two sides' Champions League semi-final, first leg and, although Hargreaves enjoyed the experience, he was surprised at the subdued nature of the home supporters.

"It was a lovely atmosphere, a great stadium," he told MUTV. "It was a bit quieter than I expected really.

"It'll be great to go back to Old Trafford on Tuesday and that'll be a proper atmosphere."

Hargreaves is the latest player to add his backing to United's Show Your Colours campaign, which encourages those fortunate enough to have a ticket for Tuesday's decider to make themselves heard.

Supporters are urged to bring scarves, flags and banners to make Old Trafford a cauldron of colour and noise. With that backing, Hargreaves is confident United can make it to the final in Moscow.

"We'll be optimistic," he revealed. "We're going to attack Barcelona, get at them and let's see if they can deal with that."