Great Britain's Morgan Lake and Dina Asher-Smith both won gold medals at the World Junior Championships in Eugene, USA.
Heptathlete Lake, 17, who had withdrawn from the Commonwealth Games to concentrate on the event, set a new world youth record of 6148 points.
She finished ahead of Cuba's Yorgelis Rodriguez to deny her rival a second consecutive World Junior Championship.
Asher-Smith, 18, clocked 11.23 seconds to win the 100m.
Ecuador's Angela Tenorio was second in 11.39 with Kaylin Whitney of the United States taking bronze in 11.45.
"I can't believe that I'm world junior champion," said Asher-Smith. "So many great people have done it before and it's really humbling to be among them.
"I've worked really hard for it for such a long time and to be able to fulfil what I really wanted to do is amazing."
Lake set a new British junior record of 1.94m in the high jump on the first day of competition and led by 169 points after four of the seven events.
She set a personal best in the javelin of 41.66m before another PB in the final event, the 800m.
"I don't even think it's sunk in yet, I'm so happy," she said afterwards. "I've wanted it for so long, I haven't really spoken about it with anyone because I didn't want to jinx it.
"In the 800m I was so dead at the end, I'd pushed at 200m to go when maybe I should have gone at 150m or 100m but I was just trying to make the line.
"The world youth record means everything too, it's what I train for so I'm really happy."