Britain's Jeremiah Azu matched his personal best of 6.49 seconds to win 60m gold at the World Athletics Indoor Championships in China and add to his European Indoor title.
The Welshman, 23, pipped Australia's Lachlan Kennedy by one hundredth of a second after a photo finish in Nanjing, two weeks after recording exactly the same time to claim European gold in the Netherlands.
Azu, who recently moved back to Cardiff and reunited with former coach Helen James, told the BBC: "I'm just excited for the future. I want to take over the world, so it's just the start.
"I've been back with Helen for three months now. Imagine what six months looks like, imagine what four or five years looks like. The plan is just to keep on winning.
"It gives me massive, massive confidence. I'm just excited now. I want to get out there and race. The sky's the limit, as people say, and I don't think the sky's the limit. There's way more than that."
Azu added: "I was a bit emotional before the final with my coach. The last few years have been very difficult for me and this morning I was thinking about it and reflecting.
"It's so important to surround yourself with people that believe in you and that care about you. If I came last, they would be the same. That is huge for me.
"Family is everything to me. I sacrificed that for the last two years. Being back with my family, having that support team around me, is huge.
"They allow me to believe in myself and that's something you can't teach. It's so important to success."
Elsewhere, Amber Anning - who claimed Olympic bronze with the women's and mixed 4x400 metres relays in Paris last summer - stormed into Saturday's women's 400 metres final in 50.79.
Kate O'Connor made more history for Ireland, claiming pentathlon silver for her country's first world indoor medal since 2006, when finishing behind Finland's European champion Saga Vanninen.
This follows her bronze in Apeldoorn, which was the first senior multi-event athletics medal for Ireland.
