They said last season the Catalan, who made his name as a player and then set about becoming one of the world's most decorated coaches in the city next to the Mediterranean, had lost his sparkle as Manchester City were dethroned.
But a 3-0 win over an outclassed Liverpool -- the club which has been his biggest rival since arriving in England in 2016 and last season ended City's Premier League dominance - proved talk of his demise was premature.
Arsenal still lead the table by four points, but their manager Mikel Arteta, Guardiola's former assistant at City, might not be sitting quite as comfortably now.
With the likes of serial title trophy winners Kevin De Bruyne, Kyle Walker and Ilkay Gundogan gone and newcomers struggling to find their feet, it has felt like City have been stuck in transition since winning the last of their six Premier League titles under Guardiola in 2023-24.
Even this season they lost two of their opening three league games, but since then, they have won 11 of their last 14 games in all competitions, the only setback a defeat by Aston Villa.
It was not just the scoreline on Sunday as Guardiola enjoyed his 716th victory as a manager.
It was the way they did it, the control they enjoyed against the reigning champions. Erling Haaland looked frighteningly good, Phil Foden showed the spark is back and Jeremy Doku was devastating at times, lighting up a damp afternoon with a majestic third goal to seal the points.
City did it all without midfield maestro Rodri, who will be back after the international break, so no wonder Guardiola was a happy man as he milked the cheers of the City faithful.
"Just want to say thank you to the players, backroom staff to give me that present," the former Barcelona and Bayern Munich manager said. "Proud to do it here in Manchester with my City.
"Now rest and come back with the energy."
Guardiola has won 12 league titles and three Champions Leagues and a sackful of other silverware since starting out as a coach of Barcelona's second string in 2007.
After his milestone match on Sunday, he said those early days laid the groundwork for the dynasties he has built in Catalonia, Bavaria and now in Manchester.
"I think my period at Barcelona B is the foundation for many things," he said. "To realise myself that I was able to do it and learn a lot. I will never forget the guys in that first season.
"For me, it has been so special to make 1000 games in front of my family and especially against Liverpool."
Guardiola said he had a "good vibe" about the current season, and should they maintain the consistency they are now showing, they will be there or thereabouts next spring.
If anyone knows how to navigate the way to glory, it is Guardiola, and he was quick to remind people of that on Sunday.
"The team that wins the Premier League is when every month the team is growing, and you see the feeling that the team grows and grows and grows," he told reporters. "Then you arrive at the end fighting for the title. It's not the team in September or October at the top.
"I said to the guys, 'Don't do it today because Arsenal didn't win (on Saturday)'. Do it for ourselves against the champions of England. Show them we are able to be there.
"Today I think we proved it."