Chelsea and Liverpool were also keen on the ex-Manchester United forward, who told City's website: "This will be a very challenging season for me - I have no assurances about my place and must win the respect of my team-mates as I fight to be first choice. Then it is the World Cup next summer. I will work hard to achieve these goals.
"It was important to speak to Pablo, and he talked in a wonderful way about City - it was good to be able to get his input. And Diego is very happy and very supportive of my move. He wants his players to be happy at their club."