Antonio Valencia ends Blackburn Rovers' resistance to stretch Manchester United's lead at the top of the Premier League It was another of those nights when Manchester United exuded anything but the impression of imperious champions-elect, yet the only image which really mattered came off camera, when 7,000 delirious fans in the Darwen stand invited Sir Alex Ferguson to give them a wave. He thrust his clenched fists to the heavens like a man who felt he had crossed another Rubicon. The manager reflected last night that the decisive goal "coming so late in the game typifies the history of this club" and United's experience of these run-ins is certainly counting in the way that Roberto Mancini had feared. Ferguson observed after his side had extended their lead to five points and that City's superior goal difference had been reduced from 18 to one, though a more significant encapsulation of the way they have wrested back supremacy is offered by the ten-point swing in United's favour since 3 March, when City led the table by five points. United have won ten games in 11, seven in succession. This is not a vintage United, whatever the league table might say, but it is one which knows more ways of winning than that City practice of pulling opponents apart. Last night required some sublime defending - three imperious saves from David De Gea in the course of United's 16th clean sheet and a late tackle from Rio Ferdinand which Steve Kean justifiably felt would be one of his best for several seasons - as well as the grace under pressure to convert their growing menace into a goal. The player who stepped up to score it has quietly established himself as the most significant one of all in United's inexorable march up the hill to a position where they can definitely discern a 20th championship. Antonio Valencia, one of the least imposing of United's players but the one Ferguson told when he arrived at Old Trafford that he must "score goals at every opportunity" to rectify a record of seven in three years. Valencia wasn't sure if he intended to shoot or score when he struck across the ball with the outside of his right foot last night, but it took his side a big step towards domestic supremacy. Ashley Young's second, five minutes later, which left United with a hand on the trophy again, was the natural progression: 38 passes and two minutes of continuous possession before Young collected the ball outside the penalty area, turned onto his right foot and whistled a shot into the bottom right-hand corner. Ferguson saw Ryan Giggs' arrival as significant, too, though De Gea's performance - three months after his grisly performance in a losing cause against the same opposition at Old Trafford - revealed why the manager insisted on buying him when some of his advisers looked elsewhere. He pulled off his saves in a first half when the home side displayed the decisive pace which United, with their intricate patterns, somehow lacked. Junior Hoilett's arced shot from 20 yards, after he had danced around Michael Carrick and which De Gea twisted to claw over the bar on 17 minutes, was the outstanding moment of the first period. Martin Olsson provoked a similar stop just before half time and, from the resulting coroner, Grant Hanley's header called on De Gea to leap and save with his fingers again. The mystery was how Rovers goalkeeper Paul Robinson had barely been called upon to muddy his gloves given United's overall control. In part, the profligacy of Ferguson's players was the cause. They were given an alarming amount of space in the Rovers box at time but squandered it and Javier Hernandez lacked the decisive finish he would have shown last season. He slid a left-foot shot past the post after Wayne Rooney had lifted the ball over midfield to him just five minutes in. United were losing their way when Morten Gamst Pedersen drove home a ball into the net for a goal chalked off because the ball had gone beyond the dead ball line before Steven Nzonzi hooked it across. Then that crucial challenge from Ferdinand showed what Ferguson meant earlier this season when he said the defender must make up in other ways what he lacked in pace. Yakubu had edged in ahead of him to meet Marcus Olsson's 76th-minute cross but Ferdinand somehow twisted to intercept it as the Nigerian shaped to meet it. Valencia's intervention was more emphatic when it came. "If you don't try to shoot you don't find out if you can score like that," Ferguson said, "he got amazing power on it." Young had been on the field for Paul Scholes for seven minutes when he added his. Steve Kean took justifiable hope from all this, despite being back in the relegation zone. "If we can play like that for 80 minutes we will get enough points," he said. But Ferguson had his own message. "Listen," he said last night. They are all big games now. It doesn't matter [that we are playing] next Sunday, next Wednesday, the Sunday after that, they are all big ones. Bookmakers have them 1-8 on for the title after last night. Roberto Mancini's hopes seem very forlorn.