A Practice Bout

To complete this quest, go to The Azure Span location, located on the Dragon Isles mainland. There, at the coordinates: /way 14.22, 47.58, you will find Gwosh (a huge toad). Engage in a duel with him and defeat him to complete the quest.

Notice:

There is a secret pet that can defeat Gwosh alone. Its name is published in the article The best battle pets in WoW at number 1.