Pep Guardiola's most humiliating defeats: From Champions League crushings to Arsenal thrashing - ranked

This was Guardiola's first game back at Camp Nou in the opposing dugout, as he came up against former team-mate and friend Luis Enrique. His Bayern side went into the game reeling from a deep injury crisis, and Robert Lewandowski had to wear a face mask after recently injuring his nose.

Facing a Barcelona attack of Messi, Suarez and Neymar that was firing on all cylinders, Guardiola decided to go against his usual tendencies by trying to keep it tight and make it back to Munich with the Champions League semi-final still alive. The plan was going well, too, until Messi broke the deadlock in the 78th minute. That opened the floodgates, and moments later the Argentine span around Jerome Boateng and left him on his backside to score the second, before Neymar added the third deep in added time.

It left Bayern with an unsurmountable deficit for the second leg, and although they regained some credibility by winning 3-2, Barca advanced to the final, where they beat Juventus to complete the treble, Luis Enrique emulating Guardiola's achievement from six years earlier.

Guardiola's first Champions League campaign at City threw up what should have been an emotional return to his former club, yet it was far from a happy occasion.

In the pre-match press conference, the coach went on a rant against Barca's then-president Josep Maria Bartomeu after being accused of trying to sign Messi for City. He then sprung a surprise before kick off by sensationally leaving Sergio Aguero out of his line-up, and things started to go wrong as soon as the game kicked off.

Messi gave Barca a first-half lead after Fernandinho fell over in the penalty area, before Claudio Bravo, who had signed from Barca the previous summer, was sent off for handling outside the area after giving the ball straight to Suarez. Barca took full advantage of the 10 men, as Messi completed his hat-trick before Neymar rounded off a sorry evening for the former Blaugrana captain and legendary coach.

The wheels were just starting to come off City's season after four defeats in a row in all competitions, but there was hope that the team would be able to regroup after the November international break and find their feet. Guardiola had also raised morale around the club by agreeing a new contract days before the visit of Tottenham.

And yet he must have been looking for escape clauses as he watched his side be cut down by Spurs. Birthday-boy James Maddison struck twice - with the help of shoddy City defending - to put the visitors in dreamland in the first half, and they never looked back. Pedro Porro added a third after half-time, and when Timo Werner savaged Kyle Walker to lay on the fourth goal for Brennan Johnson, Guardiola's heaviest-ever home defeat as a manager was confirmed.

This was the season in which the brilliant rivalry between Guardiola and Jurgen Klopp, which would go onto define a half-decade of English football, truly began. Liverpool had earlier become the first team to beat City all season in their formidable charge towards the Premier League title, winning an epic game at Anfield 4-3. Neutrals were therefore delighted when the two teams were paired together in the Champions League quarter-final, with the first leg taking place on Merseyside.

City's bus was besieged before kick off amid a scorching Anfield atmosphere, and the Reds blew their visitors away on the pitch too, as Mohamed Salah, Alex Oxlade-Chamberlain and Sadio Mane all netted inside the opening 31 minutes. Guardiola looked on in disbelief as his side had no response for the remaining hour or so, or in the second leg at the Etihad Stadium, which they lost 2-1 despite playing far better.

As if fighting it out for two consecutive title races wasn't enough, more hatred between Arsenal and City was sown in 2024-25 as, in the first fixture between the two sides at the Etihad Stadium in September 2024, John Stones' last-gasp equaliser and Erling Haaland's subsequent throwing of the ball at Gabriel Magalhaes' head and "stay humble" jibe towards Mikel Arteta caused Gunners fans to fume.

Arsenal had five months to dwell on that game and issued the most emphatic of responses. Martin Odegaard got City off to the worst possible start by robbing Manuel Akanji and scoring in the second minute, and while Haaland may have equalised in the second half, Arteta's side came right back at the champions, restoring their lead less than a minute later with Thomas Partey's deflected goal before Myles Lewis-Skelly, Kai Havertz and Ethan Nwaneri sunk their claws in, inflicting the heaviest defeat yet on Guardiola in his 17 years as a manager.

Guardiola's Barca had eliminated Real Madrid in the Champions League semi-finals back in 2011 when his rivalry with Jose Mourinho was at its most toxic. But while Mourinho's successor, Carlo Ancelotti, played none of the mind-games his predecessor revelled in, he still managed to out-manoeuvre the Catalan in both legs three years later.

Los Blancos edged a tense and tight first leg in the Spanish capital 1-0, but Bayern fancied their chances back on home turf. After dominating possession with little reward at Santiago Bernabeu, Bayern's players thought the best way to win was to go for all-out attack and Guardiola, for once, let himself be swayed by the popular clamour. He deployed an ultra-offensive 4-2-4 formation after initially considering playing 3-4-3 to flood the midfield, and told his players in the pre-match talk: "Lads, this is not about going out and having a good time. You are going out there to do some damage. Go for the jugular. You are German, so be German and attack."

But the plan turned out to be a disaster as Madrid raced into a 3-0 lead before half-time thanks to two goals from Sergio Ramos and one from Cristiano Ronaldo, who sunk his claws into Bayern once more in the 89th minute.

City's latest defeat to Arsenal might have been heavier, but it ultimately cannot compete with this match on the annoyance scale for Guardiola, who has still not forgiven himself for letting his players dictate the tactics. He furiously admitted to his friend and author Marti Perarnau that: "I got it wrong, man. I got it totally wrong. It's a monumental f*ck up. A total mess. The biggest f*ck up of my life as a coach."