Manchester United's Wayne Rooney (L) is congratulated after scoring a penalty
Two goals from Wayne Rooney, including a controversial penalty won by Ashley Young, helped Manchester United reclaim a five-point lead in the Premier League following a 4-0 win over Aston Villa.
With United owners the Glazer family making a rare appearance at Old Trafford, Danny Welbeck and Nani were also on the mark as Sir Alex Ferguson's team closed in on a 20th English league title.
Should United and second-placed neighbours City achieve the same results in their next fixtures, on Sunday, then Ferguson would see his club make mathematically certain of that title with victory in the Manchester derby at the Etihad Stadium on April 30.
Before Young's early intervention, United survived a scare inside the opening minute as Stephen Ireland's through ball sent Andreas Weimann bearing down on goal only for the Austrian to shoot too close to United goalkeeper David de Gea who saved comfortably.
But as United quickly gathered steam, there was a sense that Villa might be left to rue such a miss and, just six minutes into the game, that certainly appeared to be the case.
Former Villa winger Young skipped into the area and tripped, theatrically, over Ciaran Clark's outstretched leg.
Young, who found himself at the centre of a similar controversy after a disputed penalty against QPR last week, clearly made contact with Clark.
But questions will be asked of the manner in which he fell to ground and the haste with which referee Mark Halsey pointed to the spot.
Rooney had little interest in the debate, however, and confidently placed his penalty past the dive of Shay Given into the bottom right-hand corner for his 30th goal in 39 games for United this season.
Rooney appeared greedy to add to his tally and he appeared on the end of a Young corner, helped on by Michael Carrick, to head just wide after 24 minutes before Antonio Valencia created an opening for Welbeck which struck James Collins.
Villa had moments that concerned United -- Clark headed just wide from a free-kick and Ireland curled a shot just wide -- but the remainder of the first half belonged to the home side.
Veteran Paul Scholes sent a spectacular 20-yard volley whistling just wide, connecting directly from a Young corner, and Valencia's cross was met by Welbeck whose point-blank shot was somehow kept out by Given.
United's second goal arrived two minutes from half-time, via an attack mounted after good midfield play by Carrick and Rooney.
Carrick passed wide to Patrice Evra whose left-wing cross was missed by both Collins and Nathan Baker in the middle, allowing Welbeck to slide in at the far post.
Valencia and Scholes saw shots blocked in quick succession just after the hour, following the introduction of Nani as a replacement for Young.
Villa were not aided by the loss of Clark, after a clash of heads with Evra, although his replacement Emile Heskey came close to pulling back a goal when his header, from a Gabriel Agbonlahor cross, was tipped over by de Gea.
Rooney should have done better, and killed off the game for good, in the 67th minute when rolling a shot tamely wide from 15 yards but the England forward eventually did claim United's third six minutes later.
It was a well-worked goal as Rooney passed wide to Valencia who returned the pass, wrong-footing the defence in the process and allowing his team mate to convert easily from 12 yards.
There remained only the issue of how far United could eat into City's superior goal difference and City could thank their former goalkeeper Given for acrobatic saves to keep out subsequent goal-bound shots from Welbeck and Valencia.
Deep into the four minutes of added time, United completed the scoring when Nani appeared on the end of a patient build-up, gathering a pass from defender Jonny Evans and placing his shot easily past Given's dive.