Ichi Ban has claimed rare back-to-back Sydney to Hobart handicap wins after rival Celestial was stripped of top spot by a post-race time penalty.
An international jury upheld a dual protest against Celestial, lodged by Ichi Ban and the race committee, in the early hours of Friday.
It was penalised 40 minutes, enough to see Ichi Ban rise from second to claim its third Tattersall Cup victory following success in 2017 and 2019.
It is the first time a yacht has claimed back-to-back overall honours in more than 50 years, with Ichi Ban joining Freya (1963- 65) and Love & War (1974, 1978 and 2006) as the only triple winners.
Ichi Ban and Celestial had finished minutes apart and were neck-and-neck at sea.
Celestial skipper Sam Haynes said while he respected the jury's decision it was a "very, very difficult penalty to swallow".
"As far as I'm concerned, the decision stands. There's nothing I can do about that," he told reporters.
"It's a devastating moment. I've been trying to win this race for 10 years."
The jury ruled Celestial breached race rules requiring competitors to keep a continuous watch for radio contact.
It found a personal locator beacon on Celestial was accidentally set off on Monday night in Bass Strait, which prompted the Australian Maritime Safety Authority to alert race organisers.
When organisers couldn't reach Celestial, they asked nearby Ichi Ban to make radio contact.
When there was no response, Ichi Ban set off flares which caught the attention of Celestial.
It was confirmed the beacon had been activated accidentally and AMSA was told to stand down search and rescue aircraft.
The jury ruled Ichi Ban did not alter its course as a result but preparing and deploying two flares "temporarily affected her performance".
"We'd always prefer to win on the water, there's no doubt about that. But obviously the race committee protested the same protest," Ichi Ban skipper Matt Allen said, claiming the incident cost him 14 minutes.
"It is what it is. Sailing has many rules attached to it and they're important to abide by, especially the ones related to safety.
"There was a potential man overboard on Celestial and we were trying to obviously contact them."
Haynes said his crew didn't know it was unable to hear the radio and always raced with a safety first approach.
"The problems with communication in this race were not just isolated to Celestial," he said.
"We raced the race of our lives. To have won it fair and square would have been something we would have deserved."
Haynes said he thanked Ichi Ban for setting off the flare and alerting them to the problem.
"I thought it was a gesture of good sportsmanship, and it was. But I didn't realise we were going to be a) protested by them or b) be protested by the racing committee," he said.
"It's not actually good for the sport to have these technicalities.
"This is the most important race in Australia, potentially one of the most important races in the world and this is the way it's gone."
Ichi Ban arrived in Hobart with its red protest flag raised but Allen didn't initially indicate whether one would be lodged.
In 2017, a successful protest over a near collision resulted in supermaxi Wild Oats XI copping a one-hour penalty and losing line honours to LDV Comanche.
Allen, who has sailed in 31 Sydney to Hobart events, said early conditions that forced more than a third of the 88-strong starting fleet to retire were brutal.
"The crew is elated. We enjoyed the champagne ... and just keen to celebrate."
Supermaxi Black Jack claimed line honours this year in the slowest time since 2004.