Miss Xian narrowly oupointed Bothair Clei in a pulsating climax to the Woodlands Park 100 Club Leinster National at Naas.
Three miles in testing conditions faced the eight runners in the feature event of the afternoon and Allied Victory cut out much of the running before Mark Enright bustled Miss Xian to the front rounding the turn for home.
Sonny B travelled ominously well into the straight and joined Miss Xian on the run to the final fence, with Bothair Clei also in contention to make it a three-way battle on the run-in.
Bothair Clei looked set to triumph after hitting the front, but 9-2 chance Miss Xian roared back and the two passed the post virtually as one.
After a brief wait, the judge called Fran Flood's mare the winner by a nose.
Enright said: "I didn't know (if I'd won). The angle can be very deceiving here.
"She's tough and I wanted to make plenty of use of her. I wanted to ensure we went a good pace all the way and I wanted to get on terms jumping the last down the back. I really needed to kick on as she just gallops."
Flood said: "That's worth a lot. It's a great race, the Leinster National.
"We took a big chance being 6lb out of the handicap, but that's her third win around Naas and she's tough and she stays.
"It's a black type race and it's worth a lot to a mare, so it's worth taking a chance.
"I suppose the three-mile-five (furlong) in Punchestown would be a race that springs to mind. We'll see what the handicapper does to her."