You will get this from the quest "The Warble of a Smitten Knight", which you will obtain when you reach the Tourney Grounds. The Tourney begins with shooting, then racing and the duelling last. You don't need to have a "flawless" victory in each category, you just need to win all three and then defeat the champion at the end. If you lose any of the competitions, then you won't get the trophy.