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."
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.