Cesc Fabregas netted the only goal of the game as Barcelona won 1-0 at Celtic last night.
Hoops captain Scott Brown saw red in the Champions League clash.
Martino played it with a straight bat when asked if Neymar overreacted at the Brown red card.
He said: "I couldn't see with certainty what happened so I don't want to give an opinion.
"But certainly playing with 10 men for 35 minutes against Barcelona is something to think about when analysing the game."
Martino was happy with the way his side went forward in the absence of Lionel Messi, who was missing through injury.
He said: "We obviously prefer to play with Messi but when he is unavailable his absence cannot be used as an excuse.
"We have some excellent players. This match was the most demanding so far, Victor Valdes made important saves for us."
