LONDON (Reuters) - Manchester United manager Alex Ferguson said on Wednesday there was no danger of his side thinking the job was already done when they host AS Roma next week in the second leg of their Champions League quarter-final.

Goals by Cristiano Ronaldo and Wayne Rooney gave United a 2-0 win in the Italian capital on Tuesday to put the English league leaders firmly in the driving seat before the return leg on April 9.

"I would have taken that scoreline before the game without question," Ferguson told Sky Sports News.

"I thought it was going to be a difficult game and for most of the night it was. Cristiano Ronaldo's goal killed them a bit. We rode our luck in the first 20 minutes of the second half.

"The expectation is high here and the players have adjusted to that, they realise they are on the verge of doing something big and when you get that they stay focused. They are all very motivated as a group, there is a fantastic spirit in the place."

Rooney, bidding for his first European final, said the victory had given United a good platform to book a likely semi-final against Barcelona but remained cautious.

"With the Champions League you never know what can happen so we'll have to go out focused and with a good attitude," the striker told United's Web site (www.manutd.com). "If we do that hopefully we'll see the second leg through."

(Reporting by Martyn Herman; Editing by Sonia Oxley)