The Portugal winger made his comeback from ankle surgery during the second half of the Red Devils' goalless start to their Champions League defence against Villarreal at Old Trafford.

Ronaldo immediately sparked what had become a sluggish United attack into life, raising the prospect of Sir Alex Ferguson handing him a starting berth at Chelsea on Sunday.

However, after so long on the sidelines, the United boss may keep Ronaldo on the bench at Stamford Bridge.

"It was Cristiano's first game back tonight and it would be a big ask to think about Sunday," said Ferguson.

"He did not even play a training match, which shows you how well he has done to come back in the time he has."

The enthusiastic reception Ronaldo received from the United support should at least ease any fears that the on-off transfer saga involving Real Madrid has affected his relationship with the fans, which Ferguson feels is a big thing for the 23-year-old.

"Cristiano knows what great support he has always been given here," he said.

"He has been fantastic for us. The fans recognise how many goals he has scored."

Unfortunately for United, Ronaldo was unable to find the net this evening, ending a 12-game winning streak at Old Trafford in the competition, while match the result last time the two sides met three years ago.

Ferguson needs no reminding United were turfed out at the group stage that season, although he is not anticipating a repeat.

"I thought we did well," said the Scot.

"The players expressed themselves well, Jonny Evans hit the post and Ji-sung Park should have had a penalty in the first-half.

"There were also a number of players who will benefit from the game such as Park, Owen Hargreaves, Nani and Gary Neville, so that is positive as well."

Ferguson confirmed record signing Dimitar Berbatov faces a race against time to be fit for Sunday's meeting with Chelsea.

The 27-year-old suffered a knee injury in Saturday's defeat at Liverpool which ruled him out this evening and it seems doubtful he will be available for the weekend either.

"He has a little tweak behind the knee," he said.

"We did not want to take a chance tonight and really it is too early to say for Sunday."

Villarreal coach Manuel Pellegrini admitted United posed more of a threat after Ronaldo was introduced.

"He did cause us one or two problems," he said.

"Ronaldo is obviously a great player but he was quite fresh as well and we had one or two tired legs out there."

In fact, Villarreal came closest to scoring through Guille Franco, who might have done better going for goal in conventional manner rather than attempt the audacious flick that bounced back off the inside of a post.

"It is a difficult one," said Pellegrini.

"In a situation like that you have a millisecond to make a decision.

"It would have been a great time to score and if it had gone in we would have been talking about a fabulous goal and a great decision to do what he did.

"Unfortunately he did what he did and the ball did not go in."