Oathkeeper rounded off a memorable Bank Holiday Monday for his trainer Joseph O'Brien, who recorded four winners on his debut day as a trainer.

Successful with his first runner Justice Frederick at Gowran, O'Brien then registered his initial victory under National Hunt rules with Mai Fitzs Jack at Listowel. Zig Zag made it three by taking a handicap at Gowran (providing brother Donnacha with a double), while Oathkeeper completed the four-timer in the concluding bumper at Listowel, the Dr Louis O'Carroll Flat Race.

A winner on his debut at Roscommon last June, Oathkeeper was then beaten into second on his next start at Tipperary in October.

Sent off the 11/8 favourite today, he raced just behind the leaders in the early stages, tracking his main market rival Bel Sas

He went second with a circuit to race, and cruised alongside Bel Sas over two furlongs from home. He was pushed to the front a furlong and a half out, and he kept on strongly from there to score by nine lengths under O'Brien's sister Sarah.

Second favourite Bel Sas (5/2) finished second under Patrick Mullins for his father Willie, while Smitty Bacall (18's to 12's on-course) was a further length and a quarter back in third under David Kiely for Shay Barry.

Joseph O'Brien wasn't present at either Gowran or Listowel today. He instead went to the sales at Goffs.

His father Aidan O'Brien said afterwards: "It's very exciting and great also for JP (winning owner JP McManus).

"It (Joseph's career) is something to look forward to and he looks a fair horse.

"I think he might be going jumping now but Joseph will discuss that with Frank (Berry. McManus' racing manager).

"It has been an incredible day and how can you improve on that!"

Additional reporting by Thomas Weekes