The coach described his compatriot as a phenomenon who comes around only once in several decades and warned he has not yet reached his full potential
Messi's two goals took him joint-third alongside Real Madrid great Raul in La Liga's all-time highest goalscorer charts, with strikes from Adriano, Alexis Sanchez, Pedro and Neymar completing the rout.
"Messi will break all records he wants, and he won't be aware, he'll lose count. I'd like to think he's not at his best yet," Martino told reporters after the match.
"Messi is one of those players who come around once every 30-40 years."
Turning to the performance, the trainer praised the team effort he saw: "This was one of our best games of the season.
"Carles Puyol was subbed off because he had some discomfort in his back. But until then he played a very good game.
"The game against Valencia [a 3-2 home loss] was a step back, this is again a step forward."
Victory has lifted Barcelona back to top of La Liga and level on points with Atletico Madrid. Fellow contenders Real Madrid will travel to local rivals Getafe on Sunday.