The most revealing moment of the night arrived midway through an edgy, tense second half when Sir Alex Ferguson rose from his seat and started making his way to the dug-out. He looked like a man who had just been tipped off there were teenagers stealing the apples from the bottom of his garden.

There was a wild expression on his face and he was gathering pace, flailing his arms, little red puffs of smoke coming out of his ears.

A few moments earlier his assistant, Mike Phelan, had tried to pass on some instructions to Wayne Rooney only for the striker to turn his back and start jogging away. Ferguson was not happy about Rooney's inability to finish offone of ^­United's attacks and he madesure his player knew about it. There was a brief exchange and then Rooney ran off again, with a dismissive flick of the hand.

This was the kind of evening it had threatened to become for Manchester United. The crowd was flat, the second goal was taking an age to arrive and Cristiano Ronaldo had started running his fingers down his face in the dramatic way of his. Then Michael Carrick got away and angled his shot past David James and the mood reverted, once again, to that of champions-in-waiting. "Are you watching Merseyside?" they crowed.

The overwhelming feeling, however, was of relief and it was tempting towonder what Ferguson has said to Rooney in the privacy of the dressing room. United's manager was unhappy about the profligacy of all his front players and it is a complaint he has brought up more times than he will care to remember this season. "I don't know what to make of it, to be honest with you," said Ferguson.

"In the first half we played some of our best football for ages but then we get to half-time and it's 1–0 when it should have been 4–0 and 5–0 and, of course, as always happens, you start encouraging your opponents. They start digging, theycreate a couple of opportunities. They got to the byline a couple of times and I was saying to myself, 'They're going to score here.'

"It can be so embarrassing when you look like you might throw the game away when you should have been five or six up. I was disappointed in the result at half-time. On the one hand, it was a game in which there were fantastic opportunities and you were saying to yourself that the football is fantastic and you're enjoying it. But on the other hand you know what can happen when you don't take your chances."

Ferguson's mood had been darkened by injuries to Gary Neville and John O'Shea — both right-backs would be out "for weeks", the United manager reported — but, ultimately, this was a good night for the champions, even if the manager was distinctly unimpressed. Their lead at the top of the Premier League table is once again three points over Liverpool and, with a game in hand, his team are in a position of strength going into their last six matches.

Ferguson, however, was keen not to say anything that could be construed as over-confidence. "We are in a better position now than we were yesterday [Tuesday} morning, that's for sure," he continued. "But, having seen that second half, when we were so casual, we can't take anything for granted. We have to put our foot down all the time. I don't consider there is any leeway in this situation. I don't think we have any leeway."

The manager, one suspects, made his point forcibly to the players. "The first half we played some great stuff and had chances to put the game to bed," said ­Carrick. "At 1–0, though, they started to come into it in the second half and had a couple of opportunities, which is not ideal.

"We feel we should have been further ahead. We'd played well but it was just frustrating that we didn't finish them off as well as we could have. The second goal was important. It's always nice to score but that was a particularly ­important goal because at 1–0 it was still nip and tuck."

Rooney, in particular, was guilty of not making it an easier night than it should have been for United but, with another two players injured, Ferguson's anger also extended to the referee, Peter Walton.

"That's the disappointment because they [O'Shea and Neville] were both injured by bad tackles and the referee did nothing about it," he said. "I'm disappointed in that because you normally expect a really firm display from Peter Walton but not tonight."