The Dermot Weld-trained Hisaabaat wore down Jouster inside the final furlong to claim the McHale Engineering Maiden at Ballinrobe.
The front-running Jouster looked to have his rivals in trouble as they raced into the bend in the 1m1f contest.
Pat Smullen got a great tune from the Hamdan Al Maktoum-owned gelding as they entered the straight, however, and he swooped for a two-and-a-half length win.
The winner was third on his last visit here and has progressed with each run, scoring today at the fourth attempt.
