Jordan Thomas' bid to win a second karate World Championship title ended with an agonising defeat in his opening fight at the 2018 edition in Madrid.
Thomas became England's first world champion in the sport for 14 years when he claimed the title in 2016, but suffered a detached retina last year.
He was beaten 1-0 by reigning European champion Burak Uygur of Turkey.
"There were decisions that didn't go my way, but that's karate," the 26-year-old told BBC Sport.
"I'm so disappointed, because I beat him last month and in many ways that could have been the final."
Thomas' world ranking has slipped to 19 as a result of missing several events with eye and knee ligament injuries, meaning he was always likely to draw a highly ranked fighter in the early rounds.
"The injuries have made things difficult but I'm not making excuses and I'm more determined to return stronger and make the Olympics," he said.
England's other leading hope Carla Burkitt also lost in her opening -55kg contest against Macedonian Jovana Georgieva 2-0.
Although this was the last World Championships before the sport's Olympic debut at Tokyo 2020, there will still be opportunities for fighters to gain significant qualification points over the next 20 months.
Among the most important are the next two editions of the European Championships, as well as the crucial Olympic qualification event in Japan in early 2020.