The 22-year-old played the full game as Bayern extended their unbeaten Bundesliga run to 39 matches with a routine 2-0 home win over Eintracht Braunschweig on Saturday.
Thiago joined the German and European champions from Barcelona in the close-season, but completed 90 minutes just once - in the 4-2 DFL-Supercup defeat to Borussia Dortmund - before sustaining a knee injury against Nuremberg on August 24.
He made his comeback after three months out as a substitute in the 3-0 league victory at Dortmund last week, before then playing an hour in Bayern’s 3-1 UEFA Champions League win over CSKA Moscow on Wednesday.
Guardiola then gave the Spain international a full match against Braunschweig, and the ex-Barca coach was pleased with his "courageous" compatriot's display.
"We have a lot of injured players and Thiago wasn't fit enough to play a full 90-minute game before," he said.
"He is a courageous player but still needs time to get back to full fitness.
"I'm happy about his performance, he is a player that doesn’t know the word fear. He is very brave - I am satisfied, to come back like this after a three-month absence.
"That shows very strong character and it's a great effort from him, I'm happy with his performance."
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