The Spanish side managed to beat Estuadiantes in the final of the Club World Cup.
Guardiola said: “This time next year, we will realize what we have achieved.
“Winning in this way is very special. We knew it would be a hard game.
“Firstly, I want to congratulate Estudiantes, because they were a very tough opponent.”
He added: “It is not easy to do what we have done.
“No-one else has ever achieved it. I want to thank the players.
“We must congratulate the institution, and all the people who make this club what it is.
“Now we need to enjoy the holidays and reflect on our achievement.”