Kevin de Bruyne was the matchwinner, scoring the only goal of the night on 35 minutes.
Afterwards, Guardiola said of their opponents: "They are an extraordinary team. The shape, the quality that they play, the physicality, the pace, really incredible team.
"We struggled, we suffered a lot with the chances that they had. We were fortunate like in some way we have not been this season. We were better after the goal and we did the simple things well. The result is massively important.
"Of course, we won a lot of games in a row that helped us to be here. We won all the game since Bournemouth, except against Manchester United so that's why we are here (in the top four).
"In terms of reaching there the result was good, focus on the next nine points and if we make the nine then we will be there so it is in our hands and let's go."
Thank-you Kevin
On matchwinner De Bruyne, Guardiola declared a big 'thank-you' to the departing legend.
He continued: "Just thank you. His contribution in the game against Crystal Palace when we were 2-0 down and he delivers and today the goal again. I'm happy that it is finishing that way and we have one more game in the Etihad.
"I want the best for Kevin so it cannot be possible to have done these many years without him. He has been an incredible player but the situation is what it is.
"It's almost impossible to replace this kind of player. It is not just the performance, it is what he means to the heart for our fans for many, many years. The success we have belongs to the players."