Having spent his early career with Benfica, the Portuguese full-back says he will always hold the Club in his heart and has special memories of encounters with Sporting.
However, with City facing the Lisbon side in a two-legged encounter, the 27-year-old insists his focus will not be swayed by emotional ties.
Check out our new Champions League range
“I want to win against Sporting the same way I do against other clubs,” he said.
“I came through at Benfica but I am representing Manchester City. I want to beat Sporting - not just as a Benfica supporter, but because I want to reach the next round.
“I have some memories. When I was younger I won more than I lost, so that’s a good sign we were doing things right.
“Sporting are a big club. It’s where Cristiano [Ronaldo], [Luis] Figo and Nani came through. It will be a difficult game.
“As I said, the rivalry is one side. I am Benfica - that is a team in my heart - but I am a City player. I have a desire to win every game.
“With this squad we have, there is so much quality. We need to go into every game looking to win. We are a big team, we have quality and we know we can beat any team in the world.”
Hear what Joao had to say in the video above...
City host Sporting in the second leg of our last 16 tie on Wednesday 9 March. Don’t miss out on the chance to cheer Pep Guardiola’s men onto the quarter-finals. Get your tickets now.