Once you've started the PGA TOUR, you have the opportunity to gain rivals.
At the end of an event, you'll get a notification on screen to say that you have one, along with a picture of the golfer in question.
To win your first rivalry, you simply need to outperform your rival five times, against a variety of categories, including;
Total shots in round
Shots on Front 9
Shots on Back 9
No. of Birdies
No Bogey Round
+ a few more
At the end of every round you'll see a screen telling you which categories you've scored on.
The scores will carry over to the next round, you don't have to get five points in one go.