Jockey Marquand was also aboard when Porta Fortuna emphasised her status as this season’s leading filly over a mile in winning the Group One Matron Stakes.
Donnacha O’Brien’s 5-4 favourite, runner-up in the 1,000 Guineas at Newmarket, produced a strong closing furlong to finish a length ahead of Irish 1,000 Guineas winner Fallen Angel.
Porta Fortuna’s Leopardstown win followed her Coronation Stakes victory at Royal Ascot and Falmouth Stakes success at Newmarket.
Marquand missed the latter triumph but was back in the saddle for Porta Fortuna’s latest big win.
Soprano and Fallen Angel dictated the early pace, the latter making her return to action after that Classic triumph in May.
James Doyle asked Fallen Angel to quicken as the field went around the turn but the Irish Guineas winner had no answer to Porta Fortuna’s trademark turn of foot.
Fallen Angel held on for second with Soprano a further half a length back in third.
Porta Fortuna may now be aimed at the Chariot Stakes at Newmarket before her anticipated trip to Del Mar for the Breeders’ Cup Mile.
Day two of the Irish Champions Festival at The Curragh will have four further Group One races including the Irish St Leger.