Shrugging off another goalless European display from his side in Tuesday's draw with Spanish side Villarreal, the Scot voiced optimism that his youngsters could come through what will be an extremely testing examination without the steadying presence of the recently departed Roy Keane.

"Obviously we have a big job now in Benfica," Ferguson said. "It is a game we have to win and, for the last game in the group, it is quite an unusual situation for us."

The open nature of Group D, in which all four teams will go into their final matches knowing that victory will put them into the knockout stage, gave Ferguson grounds for his optimism, as well as a performance here that he judged much better than the scoreline suggested.

"They proved their worth in terms of the experience they had at the back, that was the strength of their team and they were very committed.

"But I think the main attacking thrust was always from us and we were a bit unlucky with the chances we had.

"It is easy to say that we didn't score a goal but we played a lot of good football at times and I think we deserved better."

Ferguson's tone was appropriately measured for, despite Wayne Rooney's best efforts, United could not complain too loudly about a result which means they have scored just twice in five Champions League outings this season.

The home side's chances were scarce once more on Tuesday but sufficient to have secured a victory that would have left them in a much more comfortable position in the group.

Lille's draw with Benfica in Tuesday's other Group D match means United could yet squeeze into the last 16 with a draw, but only if Villareal beat the French side in their final match.

Portugal winger Cristiano Ronaldo squandered the best of United's chances here, failing to hit the target with a free header from eight yards out mid-way through the second half.

"It was a good chance," Ferguson admitted. "He is a good header of the ball and you would expect him to score."

Deprived of their leading scorer Diego Forlan and playmaker Juan Roman Riquelme, Villarreal needed outstanding performances from goalkeeper Mariano Barbosa and centreback Gonzalo Rodriguez to keep United at bay, but their coach Manuel Pellegrini felt his side had merited their point.

"In the first half, Manchester United played at a very high tempo and they pushed us back but in the second half we controlled the game better and overall I think we deserved a draw," he said.

Keane's abrupt departure from Old Trafford last week was marked by a few chants from the supporters who had idolised the former United skipper.

But the tribute was cut short by Rooney's apparent determination to exact swift revenge on opponents against whom he earned a first European red card in September.

Within three minutes, the England forward had had three shots on goal.

The first, after he had swivelled on Cristiano Ronaldo's cross and squeezed between two defenders, was kept out by an excellent close range block from Barbosa.

The second, from 25 yards, spun wide and the third would have given Barbosa more work to do if Ruud van Nistelrooy had not got in the way.

That was pretty much it however in terms of clear chances until Ferguson introduced Park Ji-Sung for Darren Fletcher ten minutes into the second half.

Five minutes later, Rooney presented the Korean with the opportunity to put United ahead, but Gonzalo came to Villarreal's rescue with a good block.

Park, at least, had managed to direct his effort goalwards. An even more inviting chance was to be spurned by Ronaldo, who could only manage the faintest of contacts on Wes Brown's cross with just over 20 minutes left to play.

Gary Neville's introduction for the final quarter of an hour lifted the crowd but Keane's likely successor could not galvanise his teammates.

Rooney almost provided a dramatic finale when he cracked a fierce half-volley fractionally over with three minutes remaining. But Villarreal, tough nuts that they are, never looked like being cracked open.