As a sea of visiting supporters chanted in unison, 'The city is ours,' on a brisk April evening, a wily old Scottish mastermind arose from his spot on the bench, approached the touchline and pumped his fist in their direction with an unmistakable look of determination. He knew that his side took a major step toward achieving history.

With a 2-0 win over Blackburn at Ewood Park on Monday, Manchester United extended its lead in the English Premier League to five points, much to the pleasure of manager Sir Alex Ferguson and the army of traveling fans who rejoiced with song and dance at the prospect of a familiar barren season for fierce rivals Manchester City.

It was nerve-racking stuff at Ewood Park as United and Blackburn remained in scoreless deadlock for much of the match. But two moments of brilliance turned a potentially disappointing draw into a win that helped the league leaders get one hand on the title.

United dominated the match with long spells of possession, but they found it difficult to break down an organized Blackburn defense.

With just under 10 minutes to go, Antonio Valencia uncorked a rocket from the right side of the box that nearly ripped a hole in the net. Ashley Young went on to assure the visitors three points with an inch-perfect shot that was curled just inside Paul Robinson's left post.

The win came two days after Roberto Mancini's side was left disappointed at the Etihad as Sunderland spoiled City's perfect home record with a 3-3 draw. The Black Cats took a 3-1 lead in the second half, which it eventually squandered thanks to two quick strikes from Mario Balotelli and Aleksandar Kolarov.

The Citizens, who led the Premier League for much of the season, have now taken just five points from their last four games. The surging Red Devils, meanwhile, have managed six points from their last two games.

You are likely to get different opinions as to why United has been able to overtake City as Premier League leaders this season. Some would say it's down to Manchester United's vast experience and others may claim that Manchester City has suffered untimely injuries to key players. One or two jokers might daftly suggest that this is planet earth and to see any club other than Manchester United sitting atop England's top flight come the final two months of the season would throw the space-time continuum completely out of whack.

But this weekend, we saw one of the strongest indicators of why United is title-worthy and why City is still a work-in-progress.

That X-factor is versatility.

Manchester United's game plan at Ewood Park on Monday did not work for 80 minutes. The Red Devils struggled in the final third of the pitch with Wayne Rooney stationed wide on the left side; his creativity was sorely missed in the middle. And every cross that Valencia delivered from the right wing was easily dealt with by Blackburn's well-positioned defense.

But everything changed at the half-hour mark as Danny Welbeck and Ryan Giggs entered the match for Javier Hernandez and Phil Jones.

United reverted back into a conventional 4-4-2 formation with Rooney partnering Welbeck up front, flanked by Giggs and Valencia out wide and supported centrally by midfielders Paul Scholes and Michael Carrick.

It took the visitors roughly 20 minutes to acclimate to the change in tactics, but Ferguson saw the reward of the decision when Valencia smashed home the game-winner in dramatic fashion. Once the lead was secured with Young's strike five minutes later, United shuffled the formation once again as Rooney dropped back into midfield to help stave off Blackburn's advances.

So if you're counting, Rooney essentially occupied three different positions in the second half alone. That type of versatility made a two-point difference in the table as it helped United turn a scoreless draw into a vital win, a valuable result during a title run-in.

Compare that to the Citizens, who were virtually played off the pitch by a superior Sunderland side on Saturday.

The Black Cats defended well and prevented City from imposing its usually silky style of play, only to hit the home side on the counter and bag three goals by the 55-minute mark.

The Citizens struggled to get going and develop any sort of a rhythm. They played the same brand of soccer that they have all season, and they were figured out. It wasn't until David Pizarro entered the match 10 minutes from time that they started to play quicker; the Chilean brought a change of pace that saw the home side produce two late goals to salvage their title hopes.

Man-for-man and top-to-bottom, Manchester City has the strongest squad in the Premier League, maybe even the world.

But Mancini's assembled roster offers little in the way of versatility as his tactics always rely too heavily on David Silva and Yaya Toure. And after a long season that has left both players heavily taxed, the Citizens are beginning to pay the penalty for such a deficiency.

City and United meet at the Etihad on April 30. If both clubs win their next four league games leading up to that contest, then the Red Devils would retain the Premier League title with a win at City's ground.

No matter how strong City starts that match, you can bet that United will have the versatility to adjust and ultimately go on to claim three points once again.