Quevega continued her remarkable career by beating the geldings to carry off the World Series Hurdle at Punchestown.
The seven-year-old, a three-time winner of the David Nicholson Mares' Hurdle at Cheltenham, survived an error over the final flight to beat Mourad.
The first two horses home were trained by Willie Mullins, with Ruby Walsh on board the 8-11 winning favourite, his sister Katie on 11-2 shot Mourad.
Carlito Brigante, a long-time leader, was a creditable third at 16-1.
Reflecting on Quevega's length-and-three-quarter success in this three-miler, Mullins said: "She's an extraordinary mare for her size.
"She's just about 16 hands but as strong as an ox - I've never seen anything like she did at the last.
"To make a mistake like that and within two strides to be back up and running was pretty special. I thought she was gone or would throw Ruby off and he did very well to stay on her.
"Yet a stride after the mistake she was back up and running as though nothing had happened. Mourad never got an inch on her up the straight."
He hinted he was not overly tempted to run her in more prestigious Cheltenham Festival races such as the Champion Hurdle or World Hurdle.
"I would say she'd run in the Mares' Hurdle again as, if you're lucky enough to have a favourite for a race at Cheltenham, you run in that race."