Sir Alex Ferguson last night admitted that Manchester United had underperformed in drawing the first leg 0-0 but praised his side's professionalism, insisted that they were well placed to reach the final and vowed that the second leg would be "completely different" .

"Normally we keep possession much better than we did tonight; our transition from defence to attack was not good enough and we were not quick enough to use the ball. I am concerned about that," the manager said. "But the tie starts at Old Trafford and we know exactly where we stand now. If there is a score draw we are out; if we lose we are out. But the good news is that if we win we know we are through and, with the atmosphere and the way we play, it will be completely different. We're in a good position."

Ferguson took responsibility for United's lack of creativity, admitting that the roles he imposed on Wayne Rooney and Park Ji-sung may have affected the side, but he felt that Cristiano Ronaldo had been a threat throughout. He also claimed that, although United had been unable to create chances, they had turned in a "professional" display.

Ronaldo, for his part, complained that he "could not understand why I didn't get a second penalty". The Portuguese forward failed to score his 39th goal of the season but is determined to make amends on Tuesday. Insisting he had not altered his penalty-taking technique when he knocked his third-minute effort wide, he said: "I didn't change. I scored a few penalties in that side but today I didn't score - no problem. Now I'm going to score in Manchester."

"I thought the reaction of the Barcelona fans was interesting tonight," Ferguson added. "There were no white hankies, which showed that they were satisfied with the way their team played. Barcelona have fantastic players and I'm pleased that, while they kept the ball really well, they did not create that many clear chances. There was a period in the second half when [Samuel] Eto'o hit the side netting and got to the byline but otherwise we kept them at bay. Rio Ferdinand played fantastically."

Barcelona's coach, Frank Rijkaard, was adamant that he would not be making any concessions to defensive play on Tuesday. "It is not Barça's style," he said.

"United played quite defensively and left us few spaces and their defence was strong. I wasn't surprised that they played defensively. English teams are always like that - strong, tactically astute and well organised, with lots of players behind the ball and looking for the chance to play on the break. There's always a great difference between the way they play in the Premiership and in Europe. Tonight we saw that clearly."

Rijkaard added that he was delighted with the way his team performed and insisted that he would not change anything for the second leg. "We don't play differently or more defensively away from home; we just want to play football..." he said. "We will, of course, take into account United's strong points but we always play an attacking game. We wanted to win but the tie is still very open and we are confident. United know that we are capable of scoring away from home.

"We have to keep an eye on [Lionel] Messi still and take care with him, while [Thierry] Henry is only just coming back from a fever, but we are getting key players back. I think that, while this is not a good result, we have taken a big step forward tonight."