Upvote:1
According to your link, Nicholas Taafe was not promoted to Major General until 1739, a year after the battle of Belgrade.
Basically, he was not a senior enough officer in 1738 to have won the battle by himself. What MAY have happened was that he displayed exceptional bravery/skill that won him the 1739 promotion despite the Austrians' having lost the battle.
Irish soldiers made good "senior officers," (up to the level of Colonel or Major General) in foreign armies. But the really high commands went to members of the nobility.