In many ways, the 39-year-old Mexican must stay true to what has made him a frustrating opponent for Pacquiao in the first place.
He must use his intelligence, counter-punching ability and style to whittle away at the older Pacquiao, finding ways to win rounds and finishing strong.
It's unlikely that Marquez will be able to knock out Pacquiao, so he must pick his spots and avoid the big shots that Pacquiao is still capable of landing. He must use his knowledge of the Filipino to his advantage. We've seen him expertly dictate moments in fights against Pacquiao, whether it is sizing up the Filipino's range or taking advantage of a counter-punching opportunity. He must do the same on Saturday at the MGM Grand.
In some respects, Marquez may actually have more opportunities to do damage with his counter-punching against Pacquiao this time around. After all, the controversial loss to Timothy Bradley Jr. should make the Filipino even more aggressive, particularly more aggressive than he was when he defeated Marquez in November 2011 (albeit by a controversial decision). This may be one of those fights that Marquez doesn't have to be that active; the action will come to him.
But it's also important that Marquez goes beyond his comfort zone at times. There have been times he has dictated the pace and looked comfortable against Pacquiao, but he's never really gone for the kill in those instances, perhaps fearing a Pac-Man flurry will end the night prematurely.
Yet if Marquez doesn't capitalize on those moments he feels comfortable, this fight will likely end up with him losing via decision, like it has generally ended. He will not show enough for the judges to hand the bout to him.
Both Marquez and Pacquiao want to end this rivalry decisively on Saturday, but Pacquiao is actually under more pressure to perform. His controversial win against Marquez, coupled with his controversial loss to Bradley, has him wanting to finish his career with a bang.
Marquez can take advantage of Pacquiao's aggressiveness on Saturday and, with some good ol'-fashioned smarts, find opportunities to knock the Filipino back with his counter-punching. He needs to be aggressive when he's comfortable and sit back and wait for Pacquiao to make a mistake when he's on the defensive.