United held at the San Siro

The entire tie could have been wrapped up before half-time, with Cristiano Ronaldo somehow failing to get on the scoresheet despite having four excellent chances.

Jose Mourinho's men did improve after the break and did enough to show they will be a threat at Old Trafford in a fortnight having escaped with a goalless draw, extending his personal record against Sir Alex Ferguson to just one defeat in 13 meetings, when it could have been far worse.

Ryan Giggs was denied at one point in the first half, but the main victim was Ronaldo, who took aim with a series of free-kicks and found the Brazilian in the way every time, sometimes theatrically but always effectively. Ronaldo did beat him once with a point-blank header but it flashed wide.

The major worry, especially with a coach as wily as Mourinho in the opposing dug-out, must be United's failure to score.

It was not as though they lacked the opportunity. Lone striker Dimitar Berbatov surged clear in the box at one point, only to look up and see no-one in support as he prepared to cross.

Ferguson must have sensed Inter would finally flex their muscles after the break, and so it proved. Adriano had already flashed one shot wide when he crashed to the turf under Ferdinand's challenge as Javier Zanetti crossed. The Brazilian screamed for a penalty but TV replays suggested Spanish referee Luis Medina Cantalejo was right to say no.

But Inter tails were up and Stankovic was narrowly wide with another shot before attempting to release Zlatan Ibrahimovic, who had strayed narrowly offside when otherwise he would have been clear.

United were not quite clinging on as their opponents had been earlier. However, they were being tested and it took them some time to regain their earlier composure.

Their goal threat had become sporadic with Zanetti's far-post clearance to prevent Ryan Giggs reaching Ronaldo's low cross the summit of United's danger until the veteran Welshman was allowed to gallop into the Inter box, where his shot was blocked by Ivan Cordoba and Michael Carrick fired the rebound over.