Bravo – the understudy to number one keeper Ederson – denied Alfred N'Diaye and Conor Coady as City survived 4-1 in a shoot-out to reach the quarter-finals, following 120 scoreless minutes.
"Claudio helped us to qualify for the next round," Guardiola told Sky Sports.
"You analyse how many chances we had and how many they had and we had more, but in the special moments Claudio was outstanding.
"I don't know [if it was his best game for City] but of course he was so determined in terms of their one against ones with the goalkeeper, and then to save two penalties - so he is the man of the match by far.
"It is good for us, it is important to continue in that competition. It is a special competition for many reasons. We played with determination."
Bravo, who struggled for form and consistency in 2016-17, has made three appearances for City in all competitions this term – once as a substitute in the Premier League.
Guardiola added: "Claudio gave us the chance to go through, I'm so happy for him, the way he trains, he made a good performance.
"Last season was not easy for him, but he is a goalkeeper of a high level - he deserved that performance."