Guardiola’s 16th trophy as City boss, and the 37th of his coaching career, means he has won the Champions League, Premier League, FA Cup, League Cup, UEFA Super Cup and Club World Cup since taking charge at the Etihad in 2016.
“I had a feeling we close a chapter, we won already all the titles. There is nothing else to win. I have the feeling the job is done, (it) is over,” said Guardiola.
However, Guardiola, whose contract runs till 2025, dismissed suggestions he could now walk away.
Time for a new Pep book
“Now it’s Christmas time, buy another book and start to write it again. The last eight years it’s over,” he added when questioned whether he has the hunger to continue winning silverware.
Guardiola made history in Jeddah as he became the first coach to win the Club World Cup four times and with three different clubs.
City matched the largest margin of victory ever in a Club World Cup final, also set by a Guardiola side when Barcelona beat Santos 4-0 in 2011.
European sides are unbeaten in the competition stretching back to 2012 and there was little doubt over the outcome at the King Abdullah International Stadium once Julian Alvarez opened the scoring inside the first minute.
Fortune did not favour Fluminense as captain Nino then turned into his own net after a bright spell by the Brazilians.
City were able to coast to a fifth trophy of the year in the second half and rounded off victory with two more goals in the final 20 minutes as Alvarez squared for Phil Foden to score before the Argentine fired in his second of the night.
“We don’t do a parade (in Manchester) but I said to the players this trophy you will remember forever,” added Guardiola.
“It means you are the best team in one year in the world. It’s unique and special. It’s really cool.
“I’m really pleased for many people in the club for many years. It’s a beautiful day, I could never think when we arrived in Manchester we could do this and finish with the World Cup.”
Meanwhile, Fluminense boss Fernando Diniz stuck by his promise to stay loyal to an attacking brand of football.
But he acknowledged the huge task facing clubs from around the globe when coming up against the financial might of Europe’s elite teams at the Club World Cup.
“Money makes a lot of things easier,” said Diniz.
“With money you can have the best pitches, structures, players and you put together everything you have.
“In terms of the cash flow of the clubs this is really different for our clubs compared to the Champions League.”