Moyglare Stud Farm's Refuse to Bend captured the Group I Aga Khan's Studs National Stakes for 2-year-olds at The Curragh on Sunday, coming from behind to catch Van Nistelrooy in the final 75 yards and post a 3/4-length victory.
Trained by Dermot Weld, who won Ireland's most prestigious two-year-old race for the fifth time, and ridden by Irish champion jockey Pat Smullen, Refuse to Bend won for the second time in two career starts.
It was a quick Group 1 double for the trainer and rider, who teamed for the victory in Saturday's Jefferson Smurfit Memorial Irish St Leger with Vinnie Roe, who won the race for the second straight year.
A delighted Weld told The Racing Post, "This colt won very well first time out although he was quite babyish.
"The tactics today were to kick on whenever Pat (Smullen) thought he was ready. We wanted to put it up to the others by putting the emphasis on stamina."
Weld added: "I was slightly concerned that he might not have quite have enough pace on the good ground but he showed that he had what it took."
On future plans for the son of Sadler's Wells who won at odds of 7-1, Weld said, "He's finished for this year and I see no reason why he won't be trained for the Sagitta 2000 Guineas. On breeding, there is every reason to believe he will be a Derby horse."
The time of 1:26 was 5.1 seconds slower than Hawk Wing's record-breaking clocking in the same race last year.