The Barcelona boss believes the Argentina star has been unfairly judged on his recent goal record and defended his rotation policy at the club
Messi has 12 goals in just 13 games so far this season, but his only strike in the past month came in the Champions League draw with AC Milan.
Although the Argentine has been sidelined for much of the past three weeks with a thigh problem, he has not been immune to criticism from some quarters - something which Martino believes to be unjust.
"If Messi doesn't score three goals in a game people start to think there's a problem," he told reporters.
"Injuries happen. To Messi, or anyone."
Neymar has been in strong form during Messi's absence, contributing three goals and three assists in October, and Martino is thrilled to see the Brazilian beginning to adapt to life in Catalunya.
"Neymar is very good, but also very intelligent and very modest. That's why he's adapting easier," he said.
Barcelona emerged unbeaten in all competitions in October and secured a 2-1 win in the first Clasico of the season, but Martino admits his side have not been at their strongest during their impressive run - although he defended his persistent rotation policy.
"If you rotate, you always take a risk. When we lose, there will be criticism," said the Argentine. "But I continue to think it's the best thing to do.
"We don't like it that we don't control some games, but when it happens, we always come out of it as the best."