Relegate came from the clouds to deny stablemate Carefully Selected and provide Willie Mullins with another winner in the Weatherbys Champion Bumper at Cheltenham as he once again dominated the race.
It was a ninth win in the event for the champion trainer but a first for Katie Walsh, who delivered the mare right on the line.
Her brother Ruby was supposed to be riding the narrow runner-up, but had earlier been taken to hospital for X-rays following a fall.
Danny Mullins stole a march at the start on Carefully Selected and right until the dying moments it looked as if it would prove crucial, only for Relegate (25-1), now unbeaten in three starts, to fly up the hill.
Tornado Flyer claimed third to give Mullins a clean sweep.
Walsh said: "This is a fantastic day. I really appreciate it and I'm very lucky to be here to do it."
But the victorious jockey's thoughts were dominated by her brother, who will miss the rest of the meeting after aggravating the broken leg that only saw him return to action last week.
She said: "My heart goes out to Ruby. His bad fortune has turned into a marvellous day for me.
"All I can think of is him, to be honest. Once he's up and he's talking, that's the main thing."
She added: "She's not over-big and I knew she wanted a bit of room.
"Down the back I was struggling, but the further I was going, the better I was going.
"When she hit the rising ground, she took off. She's as hard as nails."
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