Thats a decision that your going to have to make, you have some options. You can put more effort into the game, and if he takes you to lighlty, i.e. plays his reserves, or takes it easy you may pull off the win. Also, your strategy may come into play, if you pick the right defense against his offense, etc. There is no right answer to that question.
I was able to parlay some lucky matchups, and smart game play into making the round of 128 last year as a newly promoted DIV IV in only my 2nd full time season. Of course, at that point the team I was matched up against was way superior and I choose to take it easy for the game and play my reserves as if it was a scrimmage.