The defeat brings Williams' five-year unbeaten record to an end
British sprinter Jodie Williams' 151-race unbeaten run came to an end as she finished second in the 200m final at the IAAF World Junior Championships.
The 16-year-old had already claimed gold in the 100m in Canada on Wednesday but was narrowly beaten in the 200m by 19-year-old American Stormy Kendrick.
The defeat ends Williams' remarkable run, which stretches back five years.
"I'll be happy later, but now there is still great shock at finishing second and losing my unbeaten run," she said.
"It's been a long time. I knew it would come to an end one day and that's it, it's come to an end tonight.
"It's weird that all this winning streak stuff has come out now in the press and now I've got beaten, but that stuff happens.
"I'm happy to be a medallist here and Stormy ran really well, I just couldn't catch her."
I think the expectation was way too much, but I did all I could
Kendrick ran a time of 22.99 seconds, with Hertfordshire sprinter Williams coming home in 23.19 seconds.
"I had 12 hours' sleep last night because I was absolutely shattered after the 100m. Six races in four days is an awful lot and not having enough sleep the night before last wasn't good," said Williams.
"I think the expectation was way too much, but I did all I could."
Britain's other representative in the 200m final, Emily Diamond, finished sixth with a time of 23.62 seconds.
"My legs died after the bend - I tried to get my legs to go fast but they just wouldn't listen to me, but I'm happy, sixth is good, better than expected," said Diamond.
Both British men's and women's 4x100m relay teams made it through to Sunday's finals.
The women finished second in their heat behind the United States in 44.62 seconds, while the men scraped through as fastest loser after finishing third in their heat in 40.07 seconds.
Elsewhere, Jack Green finished fifth in the 400m hurdles final and Dan Pembroke came 11th in the javelin final.
On Friday, GB's Laura Samuel and Andrew Sutcliffe won silver and bronze in the triple jump and pole vault respectively.
Samuel broke her own UK junior record with a 13.75m effort in round four to secure silver.
"Coming in I was ranked fifth so I was targeting that bronze medal and I've got the silver now, so I'm really happy," she said.
"It feels absolutely amazing, I'm on top of the world. "As soon as I knew I had it I got my flag out and started celebrating."
Sutcliffe earned third position in the men's pole vault with an outdoor lifetime best performance of 5.35m.
"It's still not sunk in yet," said Sutcliffe.
"I wasn't expecting to get a medal, well, I knew I was capable of it, but I wasn't sure I could do it."
Sarah Kelly came seventh in the women's 800m final while Matt Devereux went out of the pole vault final after three failures at 5.10m.