While the blue half of Manchester looked set to dominate the footballing agenda with a stunning 5-1 win at Spurs, United went goal crazy against a depleted Arsenal side to steal the headlines and hammer home a warning to Roberto Mancini's team and the rest of the Barclays Premier League.
In a game that had everything - a missed penalty, a converted spot-kick, a hat-trick for Wayne Rooney, a red card and 10 goals, United simply romped home 8-2.
Danny Welbeck, Ashley Young (2), Nani and sub Ji-sung Park also hit the net with David De Gea superbly saving a penalty when the lead was a slender one. Theo Walcott and Robin van Persie replied for the crestfallen Gunners, who had Carl Jenkinson sent off in the second half.
United made their intentions clear from the start with Welbeck charging down Wojciech Szczesny and looking a real threat. Tom Cleverley and Welbeck shot wide and some of the Reds' passing was mesmeric.
So it was no surprise when the hesitant visiting defence failed to deal with Anderson's clever lofted pass and Welbeck steered a looping header over Szczesny for the opener. Chris Smalling dragged wide after setting up the chance for himself beautifully but, against the run of play, Arsenal were awarded a penalty when Jonny Evans pulled at Walcott's shoulder. De Gea dived to his right to push van Persie's spot-kick around the post and earn the congratulations of his team-mates. And, from United's next attack, Young collected a header out by Armand Traore and bent an inch-perfect curler past Szczesny's despairing fingertips for 2-0.De Gea had to be alert to make a double save from Andriy Arshavin and van Persie but the champions carried the greater threat with Welbeck diving to head Rooney's cross off target. A hamstring injury cruelly ruined the young striker's afternoon, and Arshavin, who was very fortunate to still be on the pitch after a foul on Young when already booked, flashed a warning shot over the bar at the other end.
Jenkinson was also lucky to avoid a red card when hauling Young down as he sprinted through on goal but Rooney ensured his own justice was meted out by rolling the free-kick for Young to trap and then sweeping past Szczesny with the power on the shot too much for the Polish keeper.
3rd goal from Rooney`s free kick.
Rooney showed the confidence flowing through the team when testing Szczesny from his own half but there was real complacency seconds before the interval to allow Tomas Rosicky to feed Walcott, whose drive from an angle whistled through De Gea's legs for 3-1.
It was a message that the job was still far from done, and one that was taken on board as Sir Alex's side turned up the heat again in the second half. Szczesny saved well from Young and Nani chipped wastefully off target as the hosts pressed but the Gunners responded with Dea Gea superbly stopping a van Persie volley and Arshavin firing wide when Smalling was caught up the pitch.
Tom Cleverley shot weakly at Szczesny after a brilliant one-two with Young and Nani failed to convert a cross from the former Aston Villa winger but the dam broke again when Rooney repeated his free-kick feat in the first half by whipping home for 4-1 and becoming United's all-time record scorer in the Premier League.
Smelling blood, Smalling tore forward and ignored Phil Jones on the overlap to instead feed Rooney, who prodded through for Nani to net with the most outrageous of cheeky finishes. Nani then made way, along with Anderson, for Ryan Giggs and Park but the relentless attacking continued.
Rooney wedged a golf-like shot of sheer class against an upright before Park exchanged passes with Young to bury a low finish into the corner of the net. Van Persie restored a semblance of pride with emphatic finish after being played onside by Jones but United simply stepped up a gear again.
Jenkinson received a second yellow card for bundling Javier Hernandez over when he was through on goal and there were more illegal tactics used to halt the red tidal wave when Walcott tripped Patrice Evra inside the box. Rooney stepped up to seal his hat-trick with a confident spot-kick and got oven worse for the North Londoners when Young curled in to add his second from Giggs pass.
Park shot over in stoppage time but enough damage had been inflicted to the Gunners' battered pride as the home fans rejoiced on a day to remember at Old Trafford.
Rooney scores his 2nd goal to make 4-1.
