The Chile international made the switch from Championship side Birmingham last week and is set to be included in the squad for Tuesday's trip to Tottenham.
But Martinez has no concerns that the 27-year-old is up to the task.
"He has had tremendous experiences at international level," said the Spaniard.
"The first time I saw him was playing live at the World Cup in South Africa.
"Since then he has taken his football to the next level; you could see with his performances at Championship level he is ready for this football.
"We are delighted we are getting the player we all wanted and one who is ready to compete in the Premier League. The timing is perfect for us."
The player admitted Wigan's plight at the bottom of the table was of no concern after being convinced to move by the Latics boss.
"Roberto told me he has been watching me for a long time and as soon as I met with him I could feel his enthusiasm for the team and for the future of the club, which made it a very easy decision to make," he told Wigan's official website.
"I didn't take any notice of the table or league positions; I looked at the players at the club and the manager in charge and I believe we are strong enough to survive in the Premier League.
"For a long time I have admired the way the team plays and the style the manager has brought, perhaps what has been missing is a little bit of luck which I'm sure we can earn over the remaining games.
"We have a big game to get ready for against Tottenham and it's one I'm looking forward to.
"It will be tough because they are such a strong team but the only way we're going to make this a successful season is if we believe, and we have to do that tonight."
Wigan have lost their last three matches but with the team bottom of the table Martinez pointed out that at least there could be no doubt as to what is required.
"It is the easiest approach we could ever have - we have 16 games and they are 16 finals," he said.
"It doesn't matter who we are playing against or where we are playing, it is about us competing and finding that consistency we had in the second half of last season.
"It narrows down our approach and we have 16 games to achieve our aim."
