The Duke men's basketball team now has all the incentive they need to win March Madness ... because the school's most famous student (sorry Jabari) will have a gift waiting for them if they cut down the nets.

TMZ Sports caught up with Belle Knox -- the girl who was recently outed as a student putting herself through college by doing porn -- outside Headquarters Gentlemen's Club in NYC, where she just made her first strip club appearance.

After our photog admitted to being a "huge fan" of her work, Knox gave her Final 4 picks. Of course she included Duke, saying, "If Duke wins March Madness, then I will give every one of the basketball team members ..."

Watch the video to see how she finished that sentence. It's not quite as good as you'd think.