Had Son scores, Spurs may have secured a draw and kept Arsenal top of the Premier League.
Instead, backup keeper Stefan Ortega saved and ensured City went on to win 2-0.
I was so nervous, and I was praying that the ball wouldn't go in and right after the game I went to Stef and thanked him for the incredible save and for saving me," Akanji said post-game.
"He saved the game for us.
"I should have made an easy decision and kicked the ball away. I tried to play it and brought myself into a sticky situation and lost the ball. Stefan made a brilliant save and that's why you've got teammates to help you out of situations. I'm really thankful for it.
"He made some huge saves for us - I know what he's capable of. It was not the first time that he's come in and done really well - he did it at Anfield. I don't think there's a more difficult game to come in to and he's proving himself every time he plays. I'm really happy for him."