Pep Guardiola finds himself in unusual territory as he tries to work out how to turn things around at Manchester City after a surprise slump following eight years of almost unbroken success.

City's 4-1 defeat to Sporting Lisbon on Tuesday was a third straight loss for the English champions -- the first time that has happened since 2018.

Midfielder Bernardo Silva said the side were in a "dark place" after the defeats against Tottenham, Bournemouth and Sporting in three different competitions.

But Guardiola had a more optimistic outlook, pledging to "fight and not give up".

AFP Sport looks at some of the reasons for City's recent struggles after a strong start to the season.

Injury crisis

When Guardiola confirmed in late September that Spain midfielder Rodri would miss the rest of the campaign with an anterior cruciate ligament injury, it felt potentially seismic.

City's squad is packed with talent but Rodri is the man who makes them tick -- he is on a personal unbeaten run spanning 52 Premier League fixtures.

Last month the 28-year-old won the men's Ballon d'Or award in recognition of his achievements with City and Spain.

Guardiola has also been without a clutch of other stars this season.

Kevin De Bruyne returned as a late substitute against Lisbon -- his first appearance since mid-September.

Oscar Bobb, Ruben Dias, Jack Grealish and John  Stones did not travel to Portugal, while other players have also been struggling with injury, including Kyle Walker and Nathan Ake.

Silva said before City's match in Portugal that they would "never find excuses" but even a club with their vast resources do not have ready replacements for players of the quality of Rodri and De Bruyne.

Lack of hunger?

Manchester City have dominated English football for the bulk of the past decade, breaking record after record under Guardiola.

They became just the second club to win the Treble of Champions League, Premier League and FA Cup in 2023 and last season became the first club in history to win four straight English top-flight titles.

Guardiola's hunger for success appears undiminished and he has transferred that desire to his players, winning the Premier League in six of his eight full seasons at the Etihad.

The Catalan said in August that he and his players go into each campaign driven by a desire to get even better despite their remarkable success.

"Always you can improve, always you have the desire to individually be better," he said. "I want to be a better manager, and the players want to be better individually."

It is easy to exaggerate City's crisis -- they are second in the Premier League and well-placed in the Champions League despite Tuesday's defeat.

But any slight drop-off in motivation can prove fatal in the ultra-competitive world of the Premier League.

Before Guardiola, only Alex Ferguson, at Manchester United, and Jose Mourinho, at Chelsea, had managed to retain the Premier League title.

Off-field issues

Are off-field distractions having an impact at City?

Guardiola's contract expires at the end of this season and there has long been speculation over whether he will sign a new deal.

Recent reports suggest the former Barcelona and Bayern Munich boss, 53, is likely stay at the Etihad, for another year at least, which would lengthen his reign to a remarkable 10 years.

Another off-field issue with huge potential ramifications is the ongoing hearing into more than 100 alleged breaches of the Premier League's financial regulations between 2009 and 2018.

City deny any wrongdoing and have said they have a "comprehensive body of irrefutable evidence" to clear their name.

But if they are found guilty, they could face a range of punishments including a severe points penalty or even expulsion from the Premier League.

The hearing started in mid-September but the verdict of the independent commission is not likely to come before 2025.

Guardiola has been bullish in his defence of City, referring to his deep bond with the club, but he must be desperate to shed the unwanted distractions.