The fullback is delighted to have repaid the Spaniard's faith with his introduction to the Bavarians' first team, which has recently seen him called up to the Brazil squad.
The Brazilian, who has recently received a call up to represent his national side, only started eight games in all competitions under Jupp Heynckes in the 2012-13 campaign, but the arrival of Guardiola at the Allianz Arena has seen him become a first-team regular.
With Philipp Lahm moving to a defensive midfield role in the Spaniard's formation, Rafinha has made the right back spot his own.
"I had no problems last year," he told German newspaper TZ. "It's my third year here at Bayern, and even last year they wanted to extend my contract. Every day I give everything for this club, that's what I'll do in the future. I have continued to train and work hard.
"He [Guardiola] has given me self confidence again and made me play."
Rafinha's form ensured he was named in Luiz Felipe Scolari's latest Brazil squad and the defender is hoping to feature in the World Cup in his homeland later this year.
"Sure he [Guardiola] has opened the door for the national team by giving me his trust," he continued.
"I want to go to Brazil, but first I concentrate fully on the tasks with Bayern. My feet remain on the ground. If I do a good job here, the rest comes by itself."