The winger has paid tribute to his new coach for getting him back to his best form at the start of this season
The 24-year-old has started four of the Blaugrana's first five games of the season and scored the first goal of the Martino era in the 7-0 opening day rout of Levante.
Sanchez's has hardly been immune from criticism following a €26m switch from Udinese in 2011, but the Chilean says he now feels at ease with a new man in charge.
"Martino has given me amazing confidence and that gives me more freedom in the country," Sanchez told reporters.
"People press me, waiting for me to make goals and assists, but I feel very comfortable this year, I am very confident."
Sanchez will come face to face with many of his Barcelona team-mates on Tuesday night when Chile meet Spain in Geneva, yet he was quick to denounce speculation that he has any issues with one Barca player in particular.
"I have a great relationship with Lionel Messi, both on and off the pitch."