Manchester City boss Roberto Mancini says failure to buy in January cost them this season's title.
The Eastlands boss insists they should have bought a top-class centre-half when Vincent Kompany got injured.
Mancini said: "We make a mistake.
"When Vincent got injured there was still four days left in the transfer window and we should've bought another defender.
"We had a chance but didn't think Vincent would be out for 45 days. It's a problem as he's important."