The teenager was promoted from Red Bull's 'B-team' prior to the Spanish Grand Prix - a race he went on to win.
"My move from Toro Rosso to Red Bull, I think," Verstappen told GPUpdate. "You have to do well and, of course, you don't know how it is going to go… you don't know how the car is going to feel, you don't know how well you will pick everything up. It thankfully worked out well, but I had very good preparation."
However, despite a win on his maiden outing with Red Bull, it wasn't until the latter stages of the year when he began to feel more comfortable with the car.
"At the beginning it's very difficult to say what you want to change on the car, because you have very little experience with it. At the start of my second year at Toro Rosso I knew exactly how everything worked. If the brakes, steering or throttle were modified, I knew what had been changed. All this sort of thing, which ultimately made the difference.
Bahrain International Circuit - Winter testing