an lámh a bheith in uachtar agat

Etymology
Literally "to have your hand at the top"

Verb

 * 1)  to have the upper hand

Usage notes
The subject of the English expression is rendered in Irish as the object of the preposition, thus:
 * Tá an lámh in uachtar agam — "I have the upper hand"
 * Tá an lámh in uachtar ag Seán — "Sean has the upper hand"