Monday, right, sees off No Speak Alexander in Leopardstown© Photo Healy Racing
American-bred Monday skipped home on Leopardstown's quick ground to land the Listed Ingabelle Stakes which got Longines Irish Champions Weekend under way.
Seamie Heffernan sent her into an early lead from stall two in this seven-furlong assignment and the pair dictated throughout.
She was tracked by stablemate More Beautiful who came under pressure in the final three furlongs.
The leader was ridden a furlong and a half down, and was chased into the final furlong by both More Beautiful and No Speak Alexander
The latter attempted to catch her with 150 yards to travel, but Monday kept finding along the rail to score by three parts of a length at 12/1.
Runner-up No Speak Alexander went off 11/2 and finished a length and a half in front of a staying-on A Taad Moody (17/2).
Aidan O'Brien said: "We thought she was very nice the first day.
“She just found Punchestown a bit unusual around the bends. She had that run and the ground is lovely today.
“She's the first foal out of Ballydoyle. She can step into a group race fairly quick, I'd say.
“She probably learned a lot the first day and learned a good bit more today. I'd say she won't have any problem stepping up quick.
“The Boussac, Fillies Mile, all those races will be open to her.”
Monday made her debut at Punchestown earlier in the month where she came home fourth.
Paddy Power gave Monday a first show of 33/1 for the 1,000 Guineas.
Additional reporting by Gary Carson
