Anakin did win, and since Watto bet against Skywalker, he had to pay this individual after the race.
Behind the scenes
This individual can be seen twice in Star Wars: Episode I The Phantom Menace. The first is in Watto's box during the first lap of the race, and the second is after the race when Watto is forced to pay them a presumably hefty sum, due to the Toydarian later complaining to Qui-Gon Jinn.
- Star Wars: Episode I The Phantom Menace (First appearance)