Ronaldo unruffled by Nou Camp blunder

(CNN) -- Cristiano Ronaldo vowed to bounce back with a goal in the second leg of the Champions League semifinal following his penalty miss in Manchester United's 0-0 draw away to Barcelona on Wednesday night.

The 23-year-old, who has scored 38 goals this season, blazed wide of the post in the third minute after Gabriel Milito was penalized for handling his header.

It was the English Premier League leaders' best chance as Barcelona belied their poor recent form in the Spanish Primera Liga to dominate the match.

Ronaldo is United's regular penalty taker, and insisted that he had not changed his approach in the intimidating atmosphere of the Nou Camp stadium.

"I didn't change. I scored a few penalties in that side but today I didn't score -- no problem," he told Sky Sports. "Now I'm going to score in Manchester."

Ronaldo believed he should have been awarded a second spot-kick later in the first half when he was bundled over by Rafael Marquez, who was booked in the second spell for a foul on the Portugal winger and will now miss Tuesday's return match at Old Trafford.

"I think he touched me. But the referee didn't give a penalty. I don't know why, I don't understand," Ronaldo said.

"It was a tough game. Barcelona played very well, they kept the ball a lot. But I think we defended well. We played well as well. 0-0 is a good result.

"They kept the ball a lot but they didn't create great chances. We created more chances than Barcelona. Now, we're playing at home. I think we're going to win."

United manager Alex Ferguson refused to blame Ronaldo for his miss.

"I would have backed him, to be honest. He's been a bit unlucky. Maybe it's come too early," the Scot said. "You're doing well to get one penalty kick. To ask for another one... I wasn't surprised.

"We sealed off the areas where teams don't normally do well against Barcelona. They didn't make a lot of chances. Our concentration defending the space was very good.

"We should have done better with our possession. We had opportunities to counter-attack and gave the ball away too easily. But 0-0 gives us a marvelous chance."

United were forced to play a makeshift back four after center-back Nemanja Vidic was taken to hospital on Tuesday night with a stomach complaint.

The Serbia international may also miss Saturday's Premier League title showdown with Chelsea.

"We think he's doubtful. We'll do our best," Ferguson said. "Let's hope we can get him there on Saturday morning -- he'll be desperate to play."

United midfielder Paul Scholes made his 100th Champions League appearance, and earned praise from his boss.

"I thought he was one of our best players. His reading of the play outside the box was terrific. His interceptions were marvelous and he never gave the ball away," Ferguson added.

Barcelona coach Frank Rijkaard was confident that his side could score at Old Trafford.

"It won't be easy, but we're capable, we just need to maintain our strength and organization in midfield," the Dutchman said.

"It's not a great result, but we'll have to intend to score and wait to see how they do. It won't be easy for them." E-mail to a friend

All About Cristiano Ronaldo • Manchester United FC • FC Barcelona • European Football