Simon Jackson's dreams of winning a fourth straight judo medal were ended by a controversial defeat on Sunday.
Jackson's hopes of fifth straight medal suffered a dramatic blow
The Briton lost his preliminary -73kg match to Ukrainian Sergiy Sydorenko but immediately launched a sit-down protest at the referee's decision.
He was leading by a koka with just seconds remaining when Sydorenko was awarded a yuko to win the bout.
A distraught Jackson complained no score should have been given because he was off the mat.
Jackson also felt his opponent should have been penalised by competition officials for passivity, which made it difficult for him to score against the Ukrainian.
Jackson took the lead in the contest with a koka-scoring move until five seconds from the end when Sydorenko threw him for a yuko, which outscores a koka.
Jackson felt it was borderline as to whether the throw should have scored a yuko and also questioned whether the throw was inside the competition area of the mat.
At the end of the contest, the 32-year-old stayed on the mat in the traditional old style of judo protest.
GB judo coach Steve Pullen led the triple gold medallist from the mat and lodged a protest with the referee, who then studied a video tape of the contest before verifying his original decision.
"I'm devastated," said Pullen. "In fairness to the athletes, we do need a better system and video tape analysis.
"It is only the athletes that get hurt. For them it's not going to be over tomorrow, it's a four-year thing.
The Rochdale-based athlete won gold medals at three previous Paralympics but had to settle for bronze in Sydney four years ago.
He was narrowly beaten in the semi-finals of the 81kg division by eventual gold medallist Isao Rafael Cruz Alonso of Cuba - his first defeat in 163 bouts.