You've won your first Swiss Draw match, you're considered a Tournament Victor.
How to Get
Win a rated or unrated Swiss Draw match in the arena.
Bug! Testing performed on earning this badge in September, 2011, revealed that the overall winner was not determined by who won each round, but by what position they held on the team list. In two completed test matches, the players who advanced to the second round were always in slots 2, 3, 4, and 5 on the team window, regardless of who actually won the round. The players who advanced to the third and final round were always in slots 2 and 3 on the team window, again, regardless of who actually won. The winner of that round would get the badge as expected.