(CNN) -- An incident-packed final day at Cheltenham culminated in a no-less dramatic finale when outsider Lord Windermere captured the Gold Cup in heart-stopping fashion for trainer Jim Culloty and jockey Davy Russell.
The 20-1 shot beat On His Own and crowd favorite The Giant Bolster on Friday to land the most prestigious prize in the British jumps racing calendar.
A stewards' inquiry was immediately called after possible interference between the first two and third-placed The Giant Bolster, but the result stood to give Culloty a notable Gold Cup double as well as the £327,300 ($544,000) first prize.
The Irishman, who rode Best Mate to three consecutive victories from 2002-04, became just the fourth person to triumph as both jockey and trainer.
"They were the worst few minutes of my life," the 41-year-old said of his agonizing wait during the inquiry. "This was so unbelievable that I almost expected to lose the race."
Lord Windermere won the RSA Chase novices race at Cheltenham last year, but was not among the favorites for the Gold Cup.
"I'd told Davy Russell to take his time but halfway round I wondered what he was doing -- I wanted to sack him!" Culloty said.
"I told him to ride the horse to get a place but he exaggerated the waiting tactics a bit too much!
"Everyone has said the horses haven't been right but I've only got 25 horses and 10 of those would be three-year-olds, so it's pretty impressive to have two winners here, including a Gold Cup."
The owners of On His Own were celebrating after taking a gamble to pay a £27,500 ($45,000) supplementary late-entry fee for the 16-1 shot, who took home £122,800 ($204,000).
"It was well worth spending the money to supplement him," said co-owner Graham Wylie.
"I'm not at all disappointed, just proud of the horse. He did better than we expected. Coming down to the second-last I thought he might be sixth or seventh, but then his stamina kicked in and he flew up the hill."
Earlier in the day, Ruby Walsh (overnight leading jockey for the meeting) and fellow rider Daryl Jacobs were taken to hospital following falls. Both are receiving ongoing treatment.