The Camp Nou hosts looked headed for a comfortable win when they went 2-0 up on 75 minutes, courtesy of the Brazilian starlet teeing up the Argentine with a low left-cross that Messi dispatched into the roof of the net.
And Martino said the much-vaunted partnership was firing on all cylinders to silence the critics.
"It seemed to be a worry, as it was asked to me after our match with Atletico (in the Supercopa de Espana), his link-up play with Leo and now they're doing great; this is the second goal where Neymar assists Messi," Martino said.
"As long as we can work as a team, the individual performance will be brighter and we'll be a more solid team, fresher, more effective, and that can lead us to close the matches with less problems and more authority."
On Neymar in particular, Martino said: "He played a spotless match from any point of view.
"It's not just what he does attacking but also the job he does for the team even helping the defenders.
"We're very happy about what he's adding to the team."
Martino said Alexis Sanchez, who scored a 94th-minute winner, had already displayed his quality prior to his goal, and is showing signs of top form as part of Barca's all-star attacking line.
"Alexis didn't need the goal (to prove anything)," Martino said.
"It's truly welcomed as it was the one which has given the victory to us but there wasn't a real need for him to prove anything.
"I see him really confident, really fit, involved in the game.
"It's true that he can have a bad night about his relationship with the ball, but on the other hand he always offers alternatives as his job to recover the ball, it's very generous.
"These are values much appreciated by the managers."
On Sevilla's late comeback, Martino credited opposing coach Unai Emery with making some effective changes.
"I think that the substitutions from Sevilla in the second half by bringing on more attacking players caused more problems to us, but also we found some free spaces to attack which we could take advantage to close the match," he said.
