Sergio Martinez remains confident heading into his showdown with Miguel Cotto on June 7 at the Madison Square Garden, but the reigning WBC middleweight champion is not taking any chances.

In a recent interview with BoxingScene, Martinez admitted that he trained harder than before for his upcoming title defense, knowing that Cotto is the most skilled and intelligent fighter that he has ever faced in his entire career.

"I respect [Cotto] a lot," Martinez said. "Not for nothing, he's won three world titles [in three weight divisions]. I think he's the most intelligent and skilled opponent I will have faced in my career."

Martinez, who will be making his second title defense, has not fought since winning against Martin Murray in April last year after being sidelined by a knee injury.

Boxing analysts expressed doubt about Martinez's fitness heading into the fight, but the 39-year-old Argentine is not worried about his fitness, saying that he is mentally stronger than Cotto heading into their upcoming title fight.

"I do not have any anxiety," Martinez said. "I am aware of what I can do, but I'm going in there with the advantage of being mentally strong. I am very calm and confident in myself; if I wasn't I wouldn't have achieved what I have."

Pablo Sarmiento, Martinez's trainer, also played down speculation about his fighter's shape, confidently saying that "Maravilla" will be in perfect shape on fight night, while also adding that they worked hard to improve Martinez's speed.

"Sergio is going to be 100 percent when he faces Cotto," Sarmiento said. "We're doing many things and Sergio has been improving his speed. Everything is going as planned, and we have plenty of time to keep working."

When pressed to give a prediction for the upcoming Cotto-Martinez showdown, the 42-year-old trainer said that his fighter will win by knockout.

"I truly believe that Sergio will win this fight by knockout," Sarmiento said. "This is the fight that Sergio has wanted for some time. So he is working with enthusiasm and motivated to prove he is still the best."