Jamie Vardy ended his club goalscoring drought in style with a hat-trick on Saturday, as Leicester City rediscovered their Premier League title-winning form to defeat Manchester City 4-2.
Claudio Ranieri's champions were two goals up after just five minutes and made it 3-0 with 20 minutes gone, Andy King's stunner coming either side of Vardy's relief-laden opener and well-taken second.
Vardy pounced on a short John Stones back pass to squeeze home his third with 12 minutes to go, before Aleksandar Kolarov and substitute Nolito restored a measure of respectability with two late consolation goals.
A City line-up containing seven changes from the 1-1 Champions League draw with Celtic on Tuesday and employing Guardiola's typical high defensive line were badly exposed by the pace of Riyad Mahrez and Vardy.
Despite it having been Leicester's trademark in 2015-16, such punishment on the break may still have come as something of a surprise to the visitors at King Power Stadium, the Foxes having offered little indication so far this term that they retain the same devastating counterattacking threat that carried them to unexpected glory last season.
The hosts were seeking to respond to a humiliating 5-0 loss away to Porto on Wednesday, but nevertheless started brilliantly.
Three minutes in, Mahrez gathered Robert Huth's clearance and found Islam Slimani, who in turn fed Vardy. The England international's pace was too much for Kolarov, the defender only able to watch as the forward raced into the area and finished across Claudio Bravo, ending his 741-minute goal drought at club level by finding the far side of the net.
It was 2-0 after five minutes, the unlikely figure of King curling home a brilliant finish from outside the area after being teed up by Slimani, who had benefitted from Huth winning a header off a corner and nodding down into a dangerous area.
Leicester's unexpected revival continued in the 20th minute, when Mahrez collected another pinpoint long ball down the right and slid Vardy into acres of space to score easily past a stranded Bravo.
Having struggled in the absence of the suspended Sergio Aguero, Guardiola's men did begin to dominate possession late in the first half and early in the second, with Kevin De Bruyne heavily involved. The Belgian playmaker shot narrowly wide of the post in the 50th minute, having had a claim for a penalty waved away when his initial shot struck the arm of Mark Albrighton.
Pablo Zabaleta was also dangerous, seeing one shot blocked from close range at the back post before curling another narrowly wide of the far upright after cutting in off the right and bursting into the area.
City's fate was confirmed beyond doubt when Vardy took advantage of Stones' mistake, goal-line technology confirming a finish from the tightest of angles had crossed the line before being cleared.
Kolarov's late set-piece strike and Nolito's opportunistic effort at the near post served only to prevent the result from becoming one of Guardiola's heaviest ever league defeats, the Catalan having only lost by three goals twice before in the Bundesliga with Bayern Munich and never in LaLiga at Barcelona.
Leicester will now go into Tuesday's match away to Bournemouth, who lost 3-2 at Burnley earlier in the day, with renewed confidence, while City, having suffered a second damaging domestic result in succession after last weekend's 3-1 reverse at home to title rivals Chelsea, will host a Watford side buoyed by their home victory over Everton on Wednesday.