Speaking after the match, Guardiola told reporters: "Despite the decision [not to renew Hart's contract] nobody can doubt Joe's quality as a goalkeeper or what he has done in the last 10 to 12 years."
The comments come following a pledge by the CIty boss to "find a solution" to Hart's predicament.
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The 31-year-old has yet to play a Premier League match under Guardiola, and has spent time on loan at Torino and West Ham during the Spaniard's tenure. He was also left out of Gareth Southgate's World Cup squad this summer.
However, Hart was not at fault for the goal conceded in Friday's match in Chicago, in which Claudio Bravo failed to save Mario Goetze's 28th minute penalty before Hart replaced him.
New signing Riyad Mahrez played for 70 minutes before he made way for Leroy Sane. meanwhile Phil Foden and Brahim Diaz both started.
City will next face Liverpool in the tournament, on July 26.
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