Rooney's goal put his side in firm control of the tie

Sir Alex Ferguson is confident his Manchester United side can secure a Champions League semi-final spot after a 2-0 first-leg last-eight win at Roma.

Cristiano Ronaldo and Wayne Rooney each scored vital away goals to put United in pole position ahead of the second leg at Old Trafford on 9 April.

"We can't take anything for granted, but we definitely feel like we can reach the semi-finals," said Ferguson.

"It was a marvellous result. We showed discipline and composure on the ball."

Interview: Man Utd boss Alex Ferguson

The Scot said United would have to be wary of the return of Roma captain and talisman Francesco Totti next Wednesday.

"We know Totti's abilities," Ferguson said. "He's an inspirational figure for Roma, but we hope Old Trafford on a European night will be ready for us."

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"Ronaldo's goal changed the game for us. It was a fantastic header," said Ferguson.

"His spring and courage to go in front of the defender surprised the Roma player.

"It was a centre forward's header - it reminded me of myself."

Roma had a spell just after the break when they peppered the United goal, only to be undone by a mixture of keeper Edwin van der Sar's quality and a lack of ruthless finishing.

Ferguson added: "We rode our luck in the first 15 minutes of the second half. You get those breaks sometimes - and we did."

United did suffer the setback of having central defender Nemanja Vidic falling awkwardly and having to go off with a knee injury after 33 minutes.

We've scored twice away before in the Champions League Roma coach Luciano Spalletti

"I pray it is not serious, because he is such an integral part of our team," said Ferguson.

"We think it might just be a nerve injury but we can't be sure at this moment."

Roma beat Real Madrid 2-1 away from home in the last round and coach Luciano Spalletti is hoping that result will give his side confidence heading into the return leg.

"They were lucky on their scoring chances," he said. "They have players of very high quality.

"But we've got to react after what happened and reverse the situation. We've scored twice away before in the Champions League."

There was no repeat of the violent scenes that have marred clashes between the clubs in recent games, and Ferguson said: "That is a bonus and what we wanted to happen.

"Roma and ourselves have worked hard to make sure there would be no incidents."