Headed goals early in each half by Nemanja Vidic and Cristiano Ronaldo sent United through after the first leg in the San Siro had ended 0-0 and kept them on course to win five major trophies this season.

It was not a vintage performance from United but there was to be no repeat of Inter coach Jose Mourinho's victory jig down the line which greeted his Porto side's late winner at Old Trafford five years ago.

The Portuguese, who had previously lost only once in 13 meetings with United's Alex Ferguson, watched his side strike the woodwork twice and Inter wasted several other good chances.

After the deadlock in Milan, United knew that any mistakes could prove fatal but their nerves were quickly settled as Vidic put them ahead after four minutes.

The big Serbian defender lost his marker as Ryan Giggs delivered a corner and thumped a header past Julio Cesar.

United threatened a repeat of Liverpool's demolition of Real Madrid the previous night but as Inter settled the Premier League champions went off the boil.

First Vidic sliced hurriedly over his own crossbar and Inter striker Zlatan Ibrahimovic headed a Maicon cross against the bar with the goal gaping.

Dejan Stankovic and Ibrahimovic went close again as United became unusually careless with the ball to give the visitors real heart.

United were fortunate to be leading at halftime but they got the perfect boost just after the break when striker Wayne Rooney and winger Cristiano Ronaldo combined to devastating effect.

Rooney, who had been quiet, clipped a perfect cross into the area after 49 minutes and the world player of the year stole in to head his first Champions League goal of the season.

Inter refused to buckle and still retained a threat but when substitute Adriano's shot rebounded off the inside of the post they realised it was not to be their night.