SIR ALEX FERGUSON could afford to be polite.

The relief of seeing his Manchester United side secure a win with a performance which became frayed informed his review, while his perception of the importance of clipping Liverpool around the ears took into account a 24-point gap. Matches between the two clubs are steeped in history, but the days when they would decide titles are almost forgotten.

The hierarchy has become clearer in recent years; a win for United yesterday helping to preen a seven-point lead at the top of the Barclays Premier League. Liverpool have been left to endure only cameo roles in the title race, the Anfield side way back in eighth and more concerned with scrapping it out for one of the places in Europe.

It was that which allowed Ferguson to be arch ahead of their meeting at Old Trafford, the United manager claiming that he did not know where Liverpool were in the league. His point was unsaid: it doesn't matter, those boys from Merseyside have become irrelevant.

He was able to reminisce fondly after edging them out 2-1. Robin van Persie planted a low shot under Pepe Reina after just 19 minutes and United doubled their advantage nine minutes after the break, although Nemanja Vidic knew little about it when Patrice Evra's header kissed his cheek on its way in.

There was still time for some angst when substitute Daniel Sturridge forced in a goal for the visitors, but Old Trafford was able to revel in getting one over an old foe, albeit one that seems far less threatening these days. "Winning against Liverpool is important. It doesn't matter where you are in the league," said Ferguson. "Manchester United-Liverpool games are fantastic challenges. They are the two most successful teams in the country. Hopefully those three points will be very important.

"Their supporters got going after they scored and it was hard work after that. I am just glad we won the match. I haven't seen the [Liverpool] goal again but it looked a bit soft; once again the keeper has parried one out and nobody is following in the rebound.

"It lifted them. Some of our defending after that was a bit erratic and even desperate at times."

Sturridge had followed in a shot from Steven Gerrard which was parried out to the feet of the £12m man by David de Gea. The Liverpool forward had a chance to level things up shortly afterwards but spooned his shot over the crossbar, although United had become somewhat dormant and finished the match under pressure.

"But we managed to get through it," added Ferguson. "The last three or four minutes they were shoving players into the box and there was some interchange play we had to deal with. The name of the game is winning. There are moments where you have to defend. Today was one of them."

Ferguson would show mock indignation at having not been awarded a penalty when Shinji Kagawa went down in the penalty area – "[Referee] Howard Webb wasn't going to give us that" – but there was more serious cause for concern as Ashley Young had to be replaced at half-time by Antonio Valencia, and would leave Old Trafford on crutches. The United winger appeared to twist his knee in a challenge with Daniel Agger.

It was the frail first-half performance from his side which drew the greatest interest from Brendan Rodgers, a lack of belief undermining what would become an a more assured display. "I felt we were too tentative in the first half – but you can understand with young players playing here," said the Liverpool manager. "There wasn't much in the first half but any chances they had were through us giving the ball away.

"I said before we went out that when you play a rival – and this rivalry is massive – you need courage and you need to have belief.

"We wanted to pass the ball, which is great, but it has to be aggressive and we presented them with the ball and three opportunities just by being tentative. I am very proud of the fight of the team in the second half having gone 2-0 down."