British Olympic champion Jade Jones won silver in the -57kg at the World Taekwondo Grand Prix in Manchester.
Jones had been absent because of injury since a surprise quarter-final exit at the World Championships in July.
"I'm disappointed. I wanted that gold," said Jones, who lost to Eva Calvo.
"However, it's been a difficult year after the Olympics, with injury and finding motivation again.
"I now have that back and am as hungry as ever and this only makes me want it [success] again."
Jones, from Flint in Wales, beat China's Olympic silver medallist and former world champion Yuzhuo Hou in the semi-finals, and thought she had won the final with a late head-kick, but officials ignored her appeal.
"I'd used my appeal card and I just have to be happy with the points I've secured [towards the 2016 Rio Olympics] and look to next year," she said.
Jones opened her campaign with a dominant 10-1 defeat of Mexican Jessica Chavez Rivera before taking on fellow Briton Caroline Fisher in the second round.
Fisher, 31, a former European silver and bronze medallist, battled hard but had no answer to Jones's intensity, with the Olympic gold medallist winning 15-2.
Announcing her retirement after the fight, Fisher told BBC Sport: "This is it for world-class taekwondo and me.
"I have achieved a lot in my career and am proud of that but I want to concentrate on coaching and giving back to the next generation."
Jones said: "Caroline's an amazing fighter who's been around for years and years. It was great to face her and I wish her well for the future."
There was disappointment for Great Britain in the men's -68kg division with Olympians Martin Stamper and Michael Harvey, plus wildcard entry Jordan Gayle, suffering opening-round defeats.
Stamper, 27, who opened the year with victories in Spain and Germany, rarely troubled Hun Kim of Korea, losing 12-2.
Harvey, 24, had the best of the early exchanges against Vasilii Nikitin but after the scores finished level, officials deemed the Russian to have been the more dominant fighter throughout the four rounds - and thus he progressed.
Gayle, 22, performed well against former world silver medallist Maxime Potvin and was just a second from victory when the Canadian levelled, before winning by golden-point.
Many of the British fighters will return to action next week for the French Open, from 20-22 December.
The World Taekwondo Federation plans to announce details of the next phase of Grand Prix events early in 2014.