Chelsea only need to match Manchester United's result this weekend to secure their first title since 2006.
But defeat at home to Wigan would then allow United the chance to claim an unprecedented fourth successive title.
And Martinez, whose side beat Chelsea at the DW Stadium earlier in the season, insists they can do it again on Sunday.
"We have beaten Chelsea once this season plus Arsenal and Liverpool, so we know we are capable of giving any team a game on our day," he said.
"We are not playing for Manchester United, we are playing for Wigan Athletic and for the good of football everywhere.
"It is a huge challenge - that would be the case for any team going to Stamford Bridge when Chelsea need a win to clinch the title. But we will prepare for it as well as we can and we will go there determined to do our best.
"How can you feel your season is already over when you are part of a unique occasion like this?
"The mood in the dressing room is that the players are all up for it. They are ready for one final push and have a belief they can make it difficult for Chelsea.
"Football is all about dreams and it is a fantastic dream to have, that you can decide who wins the league."