The Spain international joined the Bavarians from Athletic Bilbao in the summer transfer window for a record fee, but has so far been unable to live up to the high expectations at Bayern.
Nevertheless, Martinez has stressed that his 40 euro price tag is not holding him back as it only motivates him to showcase what he can do.
"Athletic paid a lot of money for me, too. People think that I feel pressure to live up to my price tag, but it can also serve as a motivation. I want to show that I'm worth the money. It won't be easy, but I'm motivated to do just that," Martinez told Blickpunkt.
"I'm starting to feel better game by game. I'm not at 100 percent yet, but things are heading in the right direction. Last season was very long and intensive."
The 24-year-old has made 20 official appearances for Bayern so far.