Prezel Hardy the prerace favourite although having played second fiddle to the speed of Aaron Brown in the earlier rounds, came up trumps when clinching the boys’ 100m final in a time of 10.57.
The American's powerful surge at the halfway point, followed by another powerful kick, saw him dent the Canadian's hopes as he was relegated to silver in 10.79 with Italy's Giovanni Galbieri two hundredths-of-a-second in Brown's slipstream.
Surprisingly it was the USA renowned for producing a conveyor belt of sprinters, first ever youth title improving on the second places gained by Bryan Sears 10 years ago and Willie Hordge two years later.
While Hardy fully deserves the accolade of finally rewriting the record books, the Canadian authorities will be hoping the display of Brown will lead to a resurgence of sprinting in its own backyard.
Since the days Donovan Bailey and Bruny Surin, there has been a dearth of speedsters and Brown who set a national record of 10.46 in his second round will hopefully rectify the situation.
Girls sprint title stays in UK
In the girls race, teenager Jodie Williams confirmed her vast potential for the future and hopefully the 2012 London Olympic Games with a phenomenal 100 metres victory ahead of Allison Peter of the US Virgin Island and pre-race favourite Ashton Purvis from the USA.
The 15-year-old showing remarkable confidence even though last to rise from her starting blocks, powered to the gold medal ahead in a world leading time of 10.39 which bettered by 1/100sec the previous best she set in her semi final.
More remarkable was that Williams achieved her gigantic feat carrying a hamstring niggle which erupted when warming up for the opening day's action on Wednesday.
Despite that worry, the youngster who came into the meeting joint world leader with Purvis with a mark of 11.48, improved in each outing.
But the first really major highlight came in her semi final when Williams smooth style saw her gain a huge psychological advantage when tearing apart her opponents with a clocking of 11.40.
Then given the helpful lane three for the final and despite her poor start, she recovered to succeed fellow Brit Asha Philip winner of the gold medal two years ago in Ostrava.
Williams said: “It’s amazing, it’s just the best feeling ever. Another personal best and a World leading time.
I’m so pleased. I didn’t think I would be able to do better than in the semis - I thought that would be pushing it.
"But then that happened! I’m really in shock."
There was no redemption for Purvis who was seventh two years ago and has a PB of 11.40. She will be particularly disappointed after having looked good in the preliminaries although clearly not racing as fast as she expected.
Thailand’s first ever medal
Suparana S.N.A. landed a second round effort of 7.65 which assured him of the long jump gold medal and even his second best result of 7.63m with his next attempt was further than his rivals managed.
With the rain pouring down - at least it allowed a spirited crowd and slightly wet to gather under cover in the home straight and encourage the jumpers - he won ahead of Stefan Brits and Yannick Roggatz.
The South African had a best leap of 7.57m in round three while the German won the bronze medal with a clearance of 7.53m.
And Norway’s first Youth gold too!
Isabelle Pedersen producing the most consistency of any competitor in the first two days competition was rewarded with a superb 100m Hurdles victory in a time of 13.23.
Her fast, low technique over the hurdles, carried her to an easy win ahead of the USA pair of Kori Carter and Bridgette Owens who were dragged to personal bests of 13.26 and 13.39.
Pedersen's performances and her country's first ever gold medal, after running a personal best and 2009 World 100m hurdles leader of 13.35 in her heat proved that was no fluke when producing a classical performance in her semi final.
The 17-year-old Norwegian who had arrived earlier in the week with a fastest time of 13.69, handed out another dose of medicine to her rivals when clocking an incredible 13.20.
"Hurdle after hurdle I realised that I could do it," said Pedersen. Maybe this is the beginning of my new career. Last year I participated in the U16 World Championships, but this is so much more important."
It was the third fastest ever by a youth behind the 13.08 Frenchwoman Adrianna Lamalle achieved to win the inaugural gold medal in Bydgoszcz 10 years ago and the 13.14 Australia's Sally McLellan ran in her qualifier before lifting the title four years later in Sherbrooke.
Frenchman approaches World Youth best
Kevin Mayer lying fourth overnight produced a magnificent second day of consistency that not only won him the Octathlon gold medal but saw him miss the World Youth best by only four points.
Mayer might reflect if he hadn't eased up and enjoyed the crowd's applause in the final 20m, he might also have been celebrating smashing Cuba's Yordani Garcia's mark and Championship record set in Marrakech four years ago.
But after his hard slog in the eight event discipline the Frenchman who excelled by leading in the field in the last three events the high jump (2.04), javelin (58.03) and finally the 1000m (2:41.22), will have been more than happy with his 2009 World leader of 6478 points.
Qatar's Mohammed Ahmed Al-Mannai was rewarded with a PB 6232pts ahead of Germany's Steffen Klink, who almost always in a medal position, scored 6217pts also a PB.
Maksim Fayzulin will need no reminding that his poor javelin throwing ability was the deciding factor which prevented him becoming the first-ever Russian winner.
Fayzulin the overnight leader came into the last two events, 52 points ahead of Frenchman Mayer and 104 in front of Klink.
His Achilles heel proved his massive downfall his paltry effort of 39.21m lower him from top spot to fourth position where he remained with 6107pts.
Slovenia is Hammer Power
Barbara Spiler clinched the hammer crown with a best effort of 59.33 ahead of Kivilcim Kaya of Turkey and Romania's Bianca Lazar Fazecas who had best efforts of 57.91 and 56.41.
Spiler from Slovenia who led throughout the competition with her first two efforts of 56.77 and 59.03, managed to squeeze in her best throw before the heavens opened and heavy rain began to fall.
Contestants struggled in the elements and no throws - Spiler's last two were in that category - became the order of the day.
Ebony Eutsey had the fastest time of the qualifiers for the 400m final with a clocking of 53.99 but behind there were some evenly matched performances.
Sweden's Sandra Wagner ran the second quickest of 54.60 when winning her heat ahead of Michelle Brown of the USA (54.77) while Chizoba Okodogbe time of 55.18 in her victory, was only fifth fastest of the day for the Nigerian.
James Kirani the world's fastest man this year with a time of 45.45 clearly showed he will be the one to beat when coasting around the nearly full Bressanone stadium to lead the qualification for the boys’ 400m final.
The 18-year-old from Grenada leading into the straight and then slowing but looking left and right to keep any eye on his opponents, still ran a time of 46.43.
Jamaican Javere Bell had laboured much harder to win the first semi, having to fight hard to hold off Germany's Varg Konigsmark by one-hundredth-of-a-second in 48.03.
The third qualifier proved controversial with a late recall from the starter's pistol, although Nathan Kibor and Davide Re in the two outside lanes covered almost 150m before realising the other runners had stopped.
Not surprisingly they occupied the last two positions, well behind winner Awadelkarim Elyas of the Sudan who posted a season's best of 47.49.
Nicholas Kiplangat Kipkoech and Peter Langat Kiplangat who head this year's rankings, both conserved energy when controlling their 800m semi-final races.
The Kenyan pair who clocked 1:47.4 and 1:47.6 at altitude in Nairobi three weeks ago, posted marks of 1:50.85 and 1:49.45 when progressing to Saturday's final.
Ethiopian rival Fikadu Dejene also looked very impressive when winning the third semi in a time of 1:49.74.
Two Italians advance to 400 Hurdles final
The crowd erupted when Italy's Lorenzo Veroli led home the second 400m hurdles heat to guarantee his final place in a PB time of 52.50 ahead of Kenyan Jeremiah Mutai (52.65PB) and Dmitriy Koblov from Kazakhstan (52.76PB).
Beforehand Cuba's Norge Sotomayor won the first heat in a faster 52.15 with another Italian Jose Bencosme De Leon also progressing in 52.24 and Senegal's Amadou Ndiaye posting a season's best of 52.32.
Khalid Saeed Al-Saiari continuing some encouraging displays from Middle East countries, was one of seven who automatically qualified for the boys’ High Jump final when clearing 2.10.
The Qatari set a PB when keeping the best sheet alongside Dwayne Golbek of the USA and Russia's Nikita Anishchekov in a competition which lasted for two-and-half hours.
David Martin for the IAAF