Barcelona let Manchester United off the hook after failing to turn their domination into goals during their 0-0 draw at the Nou Camp but the Catalans are confident of finding the net in next week's return.
"It was a shame we didn't get the goal we deserved," striker Samuel Eto'o told reporters. "It isn't enough to threaten, we have to score. But if we play like we did today when we go there next Tuesday then we can go through.
"It's a good result as away goals count double and if we score there they will have to score two and that will be a problem for them."
Although it was United who spurned the chance to take the lead after just three minutes, when Cristiano Ronaldo suffered a rare loss of nerve and missed the target from the penalty spot, it was the home side who went on to dominate the game. Monopolising possession,
Barca bossed the midfield and penned United back in their own area as they looked for a breakthrough, but they were unable to convert the pressure into goals.
"It isn't a bad result, but we are a little disappointed given the way the game went," said midfielder Xavi. "We played well and I don't understand how we didn't manage to score.
Barca have been in poor form on the domestic front, winning only one of their last eight league games, but they were far more convincing against a subdued United.
"The players are always a bit more motivated in the Champions League and they gave everything," added Xavi. "We are happy with the image we gave and the way we played if not with the result. We have to continue like that as that's the way we like playing.
"United were a little bit conservative but that was because we pressured them so much up front and the fact that they didn't score works in our favour." Barca are hoping United will be more adventurous at Old Trafford and leave gaps at the back as they try and push forward for a goal. However, the last time they were held to a 0-0 draw at home by an English side in the first leg of the semi-finals of a European competition, they failed to go through.
United's rivals Liverpool held the Catalans at the Nou Camp in a UEFA Cup semi-final in 2001 and then beat them 1-0 at Anfield in the second leg.