The field included the winners of the English, Irish and French Thousand Guineas races with Alpha Centauri, winner of the Irish Thousand Guineas emerging triumphant in track record time.
A homebred for the Niarchos family trained by Jessica Harrington, Alpha Centauri coasted home under Colm O'Donoghue to win by six lengths taking her overall record to four wins and a second from seven starts.
Alpha Centauri raced at Royal Ascot last year finishing second in the Group III Albany Stakes after winning her first two starts at Naas.
"Alpha Centauri was very much under the radar going into the Guineas after two races on soft ground and there was no pressure on us," Jessica Harrington said.
"Today a lot of people expected her to win as she was favourite and that brings a lot of pressure. Last year we were disappointed, but that's racing. Sometimes that happens and that's why it's so great when it goes right. I've always been very confident about her. I felt she hit the front too soon, but the further she went the better she was."
Alpha Centauri is a half-sister to stakes-winner Tenth Star and is from Alpha Lupi, an unraced Rahy daughter of Champion French 3YO Filly East of the Moon, a half-sister to .Group I winner and champion sire Kingmambo from champion mare Miesque.
She is one of 50 stakes-winners for Danehill Dancer's dashing grey son Mastercraftsman, who remains on the Coolmore Ireland roster at a fee of 25,000 euros.