The Bayern legend has questioned the Catalan's decision to omit Fernandinho and Rodri from his starting line-up against Chelsea
Pep Guardiola "stole the Champions League" from Manchester City supporters, according to Lothar Matthaus, who says the head coach deserves "harsh criticism" for his team selection in the final.
City suffered a painful 1-0 defeat to Chelsea in their first European Cup final appearance on Saturday, with a first-half effort from Kai Havertz proving to be the difference between the two sides.
Guardiola opted to start the match without Rodri or Fernandinho occupying a holding midfield role and Matthaus believes his job at Etihad Stadium could be under threat after seeing a major tactical risk backfire.
What's been said?
"With his line-up he stole the Champions League from the club and the fans and he has to rightly listen to the harsh criticism from all sides," the Bayern Munich legend said of Guardiola, who coached at Allianz Arena between 2012 and 2015, in his latest column for Sky Germany.
"I am sure that there will be internal discussions about whether to part with him. The players will doubt him since that final.
"He had to try something again, present an imaginary ingenuity at the worst possible moment and totally deserved to lose.
"How can you play without a defensive midfielder in the most important game in club history, who was on the pitch in almost every game of the season, who ensures the balance, who gives everyone involved the necessary security?
"Why did he leave Rodri and/or Fernandinho out, start six attacking players and also play without a centre-forward?"
Guardiola humbled by Tuchel
Guardiola was ultimately outwitted on the touchline at Estadio Do Dragao by Chelsea boss Thomas Tuchel, who set his team up in a close-knit 3-4-2-1 formation that restricted City's threat in the final third of the pitch.
The Blues were the better team from the first whistle as Ilkay Gundogan struggled to make the sort of impact he has in recent months, with N'Golo Kante and Jorginho often kickstarting attacks after breaking up play.
Timo Werner squandered two glorious chances to put Chelsea in front before Havertz made the breakthrough just before the interval, rounding Ederson and tapping into an empty net after racing onto a through ball from Mason Mount.
Guardiola brought on Fernandinho after the hour mark and reverted to a more familiar set-up in a bid to save the game, and Riyad Mahrez came close to a spectacular equaliser with a brilliant volley in stoppage time, but Tuchel's men ultimately held on for a famous victory.
The bigger picture
Guardiola may have failed to deliver City's first Champions League crown, but after taking the club further than ever before in the competition his place in the Etihad Stadium dugout will likely remain secure for another season.
The 50-year-old also added a third Premier League title and fourth successive Carabao Cup to his collection of silverware in England this season, and he signed a two-year contract extension last November which ties him to the club until 2023.