The Catalans were trailing 1-0 for the majority of the game, but two goals from the Argentine deep into the second half eventually helped Barca to a 2-1 victory, much to the satisfaction of the goalscorer.
"We did not panic and always remained calm. We found a way to respond to their goal. We were able to build play from the back and we did not lose our heads. Luckily, the goals came in the end," Messi was quoted as saying on the club's official website.
"It’s always hard for us to win here at Osasuna. Tito Vilanova had already warned us of that before the match.
"What’s truly important is that we stay on this course - we have to keep on winning. We knew that it would be difficult to play here and, luckily, I scored again."
Barcelona resume match action on Wednesday, when they defend a 3-2 lead in the second leg of the Spanish Supercopa against Real Madrid.