Champions Manchester City suffered a surprising 3-2 defeat against Norwich City at Carrow Road in the Premier League on Saturday.
Goals from Kenny McLean, Todd Cantwell and Teemu Pukki, with the latter benefitting from a defensive gaffe by Nicolas Otamendi, gave the Canaries all three points.
Sergio Aguero got one back for City before the break to make it 2-1, and Rodri struck from distance late on, but the visitors were undone by too many mistakes at the back.
Losing to the winners of the EFL Championship last season leaves the Citizens five points adrift of leaders Liverpool, who beat Newcastle United 3-1 at Anfield earlier in the day.
The champions appeared far from their usual fluent selves during sluggish opening exchanges. Leaving Kevin De Bruyne on the bench appeared to rob City of the ability to suddenly turn patient possession into chances.
It didn't help Ilay Gundogan was struggling in the Belgian's absence, taking too long on the ball and not being daring enough with his choices.
There was a feeling Norwich could find some joy, and so it proved when McLean flicked in a superb header after meeting Emiliano Buendia's corner at the near post.
Being undone in set-piece situations is becoming a worrying habit for City:
Norwich had exploited an obvious weakness, but the credit belonged to the hosts for not being afraid to play their own enterprising game against City's pass masters. The Canaries moved the ball neatly and quickly between the lines, and their approach was best exemplified during the build-up to the second goal:
Further reward was due to the home side for such endeavour, and it came on 28 minutes when a swift counter ended with the prolific Pukki turning provider for Cantwell. Goals at this level haven't been a problem for the midfielder, who now has two in his last last three top-flight appearances.
Once again, though, vulnerabilities in a City defence sorely missing injured centre-back Aymeric Laporte had been ruthlessly exposed:
Fortunately for the Citizens, they can still rely on Aguero for goals. The Argentinian headed in his seventh of the campaign after meeting a Bernardo Silva cross in first-half stoppage time.
Aguero had given City hope of producing an unlikely comeback, but it appeared to be dashed when Otamendi gifted away possession in his own box to Buendia and Pukki profited for the sixth time already this season.
Guardiola ruled Laporte out for "five, six months" on Friday, per Stuart Brennan of the Manchester Evening News. On this evidence, the wait for his return is going to be an agonising one for City.
City's response was to bring on De Bruyne and striker Gabriel Jesus for Gundogan and David Silva. Things didn't initially improve for the visitors, though, with Aguero heading over after a deft cross from Sterling.
Another teasing delivery from Sterling saw Otamendi's header prompt a superb save from Tim Krul. However, City finally got the breakthrough they needed, albeit via a more direct route, when Rodri hammered in from outside the box.
The Citizens couldn't get any closer, though, and Norwich saw out a memorable result. For Norwich boss Daniel Farke, it's just reward for dealing with a lengthy list of injuries, including midfielders Moritz Leitner, Tom Trybull and Mario Vrancic, as well as right-back Max Aarons.
Meanwhile, this defeat will raise questions about the composition of City's squad. It almost defies belief a club with these resources and aspirations to win multiple trophies has entered the season with only three senior centre-backs, a glaring weakness amplified by Laporte's injury.
City face Shakhtar Donetsk away in the UEFA Champions League group stage on Wednesday, and Norwich travel to Turf Moor to face Burnley on Saturday.