Oh, come on, Trans, he didn't earn his position in Zeal for a talent he didn't have. You would need strategy as well as power and strength to win a battle. If his strategic skills were poor, on the other hand, perhaps he refined them while in Porre prior to the Fall of Guardia.
The only reason he kept losing was the fact that his opponents were tougher. Maybe stealing the Grandleon was the edge he needed to finally best them.