Richard Kilty, who considered quitting athletics after failing to gain selection for the London Olympics, sprinted to a stunning victory in the 60 metres at the World Indoor Championships.
Minutes after team-mate Tiffany Porter had taken bronze in the 60m hurdles, Kilty produced the greatest performance of his career to snatch gold at the Ergo Arena in Sopot.
The 24-year-old from Stockton stormed to a personal best of 6.49 seconds, edging out Marvin Bracy of the United States by 0.02secs, with Femi Ogunode of Qatar taking bronze.
Dwain Chambers, who was seeking a fourth straight medal in the event, could only finish sixth in 6.53 as the eight finalists were separated by just 0.09s.
"I can't believe it. This is a dream come true," Kilty said. "I told my dad four years ago that I would be world champion and to have done it, I feel like crying."
After an unsuccessful appeal against his omission from the team for the London Olympics, Kilty pondered quitting the sport or possibly representing Ireland, saying he felt "let down" by governing body British Athletics.
He also suffered a torn hamstring and was struggling to get by without any funding, but returned to the track in January 2013 and posted enough impressive times to be restored to the funding programme in October.
"This proves that the selectors got it wrong in 2012," added Kilty. "For the last few years all I have done is get slated by the media and people in my home country.
"I considered quitting because I had no income and had to train on the road in trainers. I couldn't afford to get to the track. Nobody's had it harder than me last year.
"Thankfully my dad Kevin persuaded me I had the talent and told me to give it another year and this is for him and all my fans and supporters. I think my dad was watching it in a pub with friends so I am sure there will be some big celebrations."
Chambers, who had scraped into the final as a fastest loser from the semis by 0.01s, said: "I'm disappointed but Kilty did a very good job. He held his nerve and kept it together and ran a very quick time.
"I'm just doing what I can to keep up with these young boys and the better man won. Richard's in good hands with (coach) Rana Reider and the move's worked out really well for him. I just wish him the best of luck.
"I didn't see it coming. When you're out there you just concentrate on yourself. I just ran and it wasn't my day."
In the hurdles, Porter was hampered by a slow start but produced a strong finish to record a season's best of 7.86 seconds, just 0.01 secs behind Olympic champion Sally Pearson. Nia Ali of the United States took gold in a personal best time of 7.80s.
"It's really bittersweet," said Porter, who won silver two years ago in Istanbul. "I'm really happy and thrilled to have brought a medal home for Great Britain & Northern Ireland because you never take that for granted.
"I know I gave up a lot in that start and it's a little disappointing not to execute your best race, but I'm very happy and looking forward to the outdoor season. I like to pride myself on performing when it matters most."
Luke Cutts had been tipped to win a first ever global medal by a British male athlete in the pole vault after setting a new national record of 5.83m earlier this year, but he could only finish eighth in the final.
Cutts needed three attempts to clear his first height of 5.40m and eventually bowed out of the competition after three failures at 5.75m.
"That's how it goes," he said. "It's difficult changing poles and having so many attempts at different heights, clearing third time on the first height and third time on the third height and second time on the second height.
"It's too much to do and changing poles is a bit difficult too. The pole was getting soft so I changed up but it didn't work out.
"It's my first major championships back in the GB team in seven or eight years. It's just a lack of experience in major championships. I'm just frustrated with how I jumped. I'll go back and watch some videos my coach has taken and learn from them, and find what I can do right."
Britain won nine medals in 2012 and will look to get as close to that tally as possible on Sunday, with European indoor champion Holly Bleasdale in the pole vault final, Shara Proctor and Katarina Johnson-Thompson in the long jump final and Andrew Osagie in the 800m final.
Andy Vernon also goes in the final of the 3,000m with Andy Pozzi and William Sharman in the semi-finals of the 60m hurdles and Asha Philip and Sophie Papps at the same stage of the women's 60m.