The £6million striker could not score on his Premier League debut as he only hit a crossbar when the Latics were humiliated 4-0 by Blackpool on Saturday.
Martinez, though, remains convinced by the Argentine's ability as Wigan prepare for a daunting meeting with Chelsea.
The Latics boss said in the Daily Mirror: "Mauro is a clinical finisher. He has that knack of being in the right place at the right time.
"I saw him play for Estudiantes and he scored over 50 goals in two years and in every competition he played to the same level.
"That is difficult to play when you play in competitions like Copa Libertadores.
"At 25 it is the perfect time for him to come to the Premier League and be himself.
"He is a real goalscorer and can score goals where other players do not see an opportunity.
"He is a real worker as well. His link-up play is good and the rest of the players appreciate that."