Tello inked a new deal with Barca just weeks after Martino's appointment.
"He is good - he's easy to talk to and is very approachable. He asked me to stay alert, work hard and my chances would come.
"We are doing okay, but gradually we will improve - we need to change a few things so that we aren't too predictable, but in essence we have to stay the same," Tello said of the adjustment.
For the big stories and the banter follow us on Twitter: @tribalfootball