The former Barcelona ace gifted a goal and could also have given away a penalty and been red carded for a lunge on Wayne Rooney.
But Guardiola claims he is more than happy with his new number one.
He said: “He is so strong. I watched the game again yesterday and saw their goal and his personality after that moment.
“That's what I was saying after the game. I was convinced by him before the game and it was the same after.
“Whether it is Claudio Bravo, Willy (Caballero) or Angus (Gunn), they are going to make mistakes in the future.
“They are not going to save all the goals. They are going to make mistakes, the opponents are going to score goals. I am pretty sure of that."