BBC Sport - American teenager Cooper Lutkenhaus produced a stunning performance to hold off Olympic champion Emmanuel Wanyonyi in the men's 800m at the Diamond League meeting in Norway.
The 17-year-old crossed the line in a personal best of one minute and 42.08 seconds to edge out the Kenyan by one hundredth of a second in Oslo, despite Wanyonyi recording his fastest time of the season (1:42.09).
Lutkenhaus was unbeaten in his five previous 800m finals this year, having claimed gold at the World Indoor Championships and become the Diamond League's youngest ever winner on his debut in Stockholm last weekend.
"This boy [Lutkenhaus] is in a good shape," said the 21-year-old Wanyonyi, who missed the event in Sweden following the birth of his first child.
"Can you believe that as an Olympic champion, you are trying to knock down a 17-year-old boy?
"I started the race in front and after 600m to go, I tried to see who is coming to push me. Then I saw him passing me so then I tried to respond. But my target today was to run my season best, to improve."
British sprinter Amy Hunt placed second in the women's 100m in 10.99 seconds, with St Lucia's Olympic champion Julien Alfred taking victory in a time of 10.76.
Amber Anning was fourth in the women's 400m as Norway's Henriette Jaeger enjoyed success, while her fellow Briton, Jake Wightman, finished fifth in the Dream Mile behind Kenya's Timothy Cheruiyot.
There was Ethiopian dominance in the women's 3,000m race, with Freweyni Hailu, Likina Amebaw, Senayet Getachew and Hawi Abera occupying the top four positions.
Hailu recorded the fastest time in the world this year, crossing the line in 8:24.22, while GB pair Megan Keith and Innes Fitzgerald finished seventh and ninth respectively.
In the final event of the evening, home favourite Karsten Warholm's time of 47.40 was only enough to earn the Swede second place behind Brazilian rival Alison dos Santos (46.89) in the men's 400m hurdles.
Australian Gout Gout did not make the same impact as fellow teenager Lutkenhaus as he finished sixth in the 200m.
All eyes were on the exciting 18-year-old for his Diamond League debut in Oslo.
But Gout never recovered from a slow start as reigning 200m Olympic champion Letsile Tebogo showed his class for victory in 19.84.
Gout clocked 20.60, well short of the Australian record of 19.67 he set in April.
"Tebogo is a great athlete, I've looked up to him for a long time and he deserved the win," he said.
"I'm happy to be here but I'll definitely go back into the workshop to work on more. There's always pressure on me but all I do is try my best and keep focusing on just having fun.
"I'm going out here against the big boys and I'll definitely come back."
Botswana's Tebogo, 23, added: "First and foremost, he should not get comfortable racing with the seniors. He still has a long way to go.
"I have seen a lot of people my age racing with seniors and it did not go well for them."