Manchester United's Wayne Rooney (top) jumps for the ball against Liverpool's Jamie Carragher during their English Premier League match at Old Trafford on Sunday.

Sir Alex Ferguson believes Park Ji-sung is fast becoming Manchester United's man for the big occasion after the South Korean scored the decisive goal in the team's 2-1 win over Liverpool.

Park's second-half header at Old Trafford on Sunday sent United back to the top of the Premier League and emphasized the 29-year-old's ability to produce his best when the stakes are highest.

In the past 12 months, Park has been transformed from a useful squad player to a key member of Ferguson's team in United's biggest matches and he has repaid his manager's faith.

Last term he scored a vital goal in United's Champions League semifinal second-leg win at Arsenal, then became the first Asian to play in a Champions League final later that season.

This year he has scored only three goals but all have been vital. He opened his account for the season in the 3-1 win at title rivals Arsenal and also scored in United's 4-0 Champions League last-16 win over AC Milan.

The Milan match showcased Park's versatility as he man-marked Andrea Pirlo, but he played a more advanced role just behind Wayne Rooney against Liverpool and responded with a goal.

"He's one of these players that we can give him roles to play because of his intelligence and discipline and we found another role for him," said Ferguson.

"It was slightly different from the Milan games but, nonetheless, really important for us. He's such a bright little lad that his courage got him the goal."

United are now two points clear of second-placed Arsenal and four ahead of Chelsea.

For Ferguson, the presence of fit-again defensive pair Rio Ferdinand and Nemanja Vidic has convinced him United can record a record 19th league title.

"I don't think anyone's getting away," said Ferguson of the challenge posed by Chelsea and Arsenal.

"We are all opening doors. But I think with Vidic and Ferdinand looking fresh - they have been out for most of the season - I think those two back to that form gives us a great hope and opportunity.

"It's at the stage of the season where winning is the name of the game. We have been very consistent in the past two or three months.

"It's always difficult to lose a goal and come back and win, it's a great quality Manchester United have and it was that quality that won us the game again."

While Ferguson closes in on an unprecedented fourth successive league title, Liverpool's dismal season took another turn for the worse.

The Reds are in severe danger of missing out on a top-four finish but manager Rafael Benitez was more concerned with berating United winger Antonio Valencia for diving to win his side's first-half penalty.

Valencia, tugged back by Javier Mascherano, won the penalty that was converted, at the second attempt, by Wayne Rooney.

The penalty decision also saw Benitez and Ferguson engage in a furious verbal battle on the touchline as the United manager claimed Mascherano should have been shown an automatic red card.