Aidan O'Brien's Iniesta battled all the way to the line to claim the Ladbrokes Loyalty Card European Breeders Fund Maiden at Galway.
Joseph O'Brien's mount (15-8) was soon disputing matters with Keyword, and made a positive move from the three-furlong pole, gaining a couple of valuable lengths on the field.
Odds-on favourite Leafcutter gave chase but despite Dermot Weld's charge flattering a furlong out Iniesta found another gear and pulled away to score by two lengths.
The winning rider said: "He's tough and he stays well, although I'm not sure if he's 100% happy on the ground. It's dead ground and testing."