Manchester United suffered a fourth-straight league defeat against cross-town rivals Manchester City on Sunday.
The Reds were forced to play with 10 men for the majority of the game after defender Chris Smalling picked up two avoidable yellow cards.
The first came after Smalling inexplicably tried to block a Joe Hart kick out, although Hart himself was lucky to escape punishment after he clearly stuck his head into referee Michael Oliver’s face.
Despite being booked Smalling threw himself into a rash challenge only minutes later to earn a second yellow card.
United was already well and truly on the back foot and had to call on David de Gea to make two stunning saves to ensure parity, and its struggles were only compounded by Smalling.
The sending off saw Adnan Januzaj substituted, with Angel di Maria moving from the left to right wing, with captain Wayne Rooney forced to the left from his initial role behind Robin Van Persie.
Michael Carrick came off the bench making his first appearance since ankle surgery in June, and slotted into central defence alongside Marcos Rojo.
United’s resillience shone through, with Marouane Fellaini impressing again in midfield, and the Red Devils made it to half-time with scores still locked at 0-0.
They needed a bit of help on the way though, as City had two good penalty shouts denied, the first after Fellaini made contact with Aguero in the box and the second after a desperate lunge from behind from Rojo on Yaya Toure.
Had Oliver called the penalty against Rojo, the Argentinean defender would have surely received his marching orders as the last man.
As it happened, Rojo did not last for long in the second half as he dislocated his shoulder in the process of another lunging tackle and had to be stretchered from the field in visible discomfort.
Nineteen-year-old Paddy McNair entered the fray to play in a back four comprised of wingman Antonio Valencia, midfielder Carrick and fellow teen Luke Shaw – who impressed throughout.
McNair was solid once again and did not looked out of place in the senior side, although one costly moment in which he lost Aguero proved the difference, with the Argentine moving smartly to avoid his markers attention and slam home from close range following a good cross from the left wing.
Manchester United responded positively to the concession and while it could not snatch an equaliser, Rooney and Van Persie created some opportunities out of nothing.
The former inspired his teammates into a very positive final 15 minutes when he turned his marker just inside his own half and beat two defenders only to be crowded out as he approached the box.
United continued to turn the screw, as City manager Manuel Pellegrini shut up shop, but could not find the equaliser it arguably deserved.