Robin van Persie was on target against his old club as Manchester United brushed Arsenal aside for a 2-1 victory that sent them to the top of the Premier League on Saturday.
The Dutchman, who joined United from Arsenal in August, needed less than three minutes to put the hosts ahead after a mistake by Thomas Vermaelen and Patrice Evra wrapped up a comfortable win with a 67th minute header.
Santi Cazorla netted in injury time for an otherwise disappointing Arsenal, who were reduced to 10 men after the break when midfielder Jack Wilshere was sent off for a second yellow card.
Wayne Rooney also missed a penalty for United on the stroke of halftime.
United have 24 points from 10 games and will remain on top if Chelsea (22 points) fail to win at Swansea City later on Saturday (1500 GMT).
Champions Manchester City, in third place on 21 points, conclude the day's Premier League action with a testing trip to West Ham United (1730).