Stormy Kendrick running the fastest 200m of her career spoiled the dream sprint double hopes of Jodie Williams when comfortably winning in a lifetime best time of 22.99.
The American thunderbolt who came to Moncton with a personal record of 23.28, exploded off the final bend to prevent her 16-year-old British rival becoming only the third woman to follow in the footsteps of Veronica Campbell-Brown and Tezdzhan Naimova and achieve the feat.
Down the home straight there was only ever going to be one winner and she was donned in an American strip, although Williams the world leader with 22.79 and down in fourth, at least got her act together and pushed herself into second ahead of Jamile Samuel to beat the Dutchwoman by 0.08 in 23.19.
Kendrick who earlier in the evening had ran the opening leg as the USA set a national 4x100 relay record in their heat, was a revelation as she became only the second American to win the coveted title since Shalonda Solomon's success six years ago.
"I’m feeling very good," said Kendrick after winning the USA's first gold medal of the Championships. "I mean, I’m just so happy I just don’t know what to say.
"'Win!'" that’s what I came to do. And we have the relay tomorrow, so we’re hoping for another gold medal in that."
"I had great competition, but I knew I had to run my race and just be patient and not stress near the end.
"This is my last race of the season, so I’m happy to go out with a gold medal.
"I’ve been running forever, since I was small, and I’m good at it, so my heart’s in it. God gave me this talent."
Williams who looked exhausted in the final straight, said: "I had 12 hours sleep last night because I was absolutely shattered after the 100 metres.
"Six races in four days is an awful lot. Not having enough sleep the night before last, wasn’t good."
"But last summer's World Youth double winner, after losing out at the higher level and respectful of the high quality of opposition, admitted: "I think the expectation was way too much, so I did all I could."
Samuel who has been a revelation for the Netherlands, said: "I just wanted to run a little bit faster but this is cool too, because I never thought I would win two medals here so that is great.
"It was a great competition. The other women really pushed me and I’m happy with the bronze."
Historical 200m gold for Japan
World leader Shota Iizuka duly took the 200m gold medal - the first ever over the distance for Japan - and even if the three 100m medallists had been present, they would have struggled to beat the inspired Asian speedster.
Iizuka came into the home straight line abreast with four of the other medal hopefuls, but a hitch kick and substantial burst of speed carried him into pole position 50m from the line.
It was a lead he had no intention of giving up as he crossed the line well clewar of Aliaksandr Linnik and to the delight of the home crowd Canada's Aaron Brown.
Linnik who set a Belarusian record in his semi, on this occasion was 0.08 slower in 20.89 while Brown lifted by a deafening roar from the patriotic spectators, belted out a PB 21.00.
Iizuka after his milestone victory, said: "I’m feeling amazing. Just one word - amazing. This is the greatest opportunity I’ve ever had, to run in such a prestigious competition, so I just tried to do my best."
He revealed: "For me, I was almost trying to intimidate the others, so for me it was fun. I was confident.
"My strategy was to keep up my stamina, and just do my best. Don’t hesitate, just focus.
Linnik in what has been a big breakthrough in Moncton, said: "It was easier to run this time, and I’m very happy with second place at the World Championships.
"I feel the time could have been better, but I’m happy.
"The competition was strong, because it’s the world level, so I felt more pressure this way, but otherwise it was just a regular competition."
Brown who revelled on his lap of honour said: "I was running blind from the outside so I did not see anybody until I got onto the straightaway.
"They all started to pull away so I finished as strong as I could and I’m very happy to get the bronze medal.
The Canadian insisted: "I really pushed it at the end. The crowd was a motivating factor for sure. I could hear them cheering me on so I wanted to give them something to be proud of.
"It was nerve-wracking waiting for the time to be posted. I honestly had no idea how close I was. I just kept saying: 'Please God, please don’t leave me off the podium again."
"And when they flashed my name I just had to go to the ground and thank God."
Jehue Gordon tops 400m Hurdles
Jehue Gordon duly atoned for his unexpected elimination at the last Championships by winning the 400m hurdles - but it wasn't the expected walkover many expected.
In a thriller the Trinidad and Tobago star held on to score a narrow victory in 49.30 by just 0.16sec from the fast finishing Takatoshi Abe of Japan with the US Virgin Islander Leslie Murray third in a season's best 50.22.
Gordon fourth in last summer's World Senior Championships looked unstoppable when a clear leader down the backstraight, but coming off the final bend Abe the Asian junior champion began reeling in him.
The nearer they got to the line the closer Abe closed on his more experience rival who grimacing, just managed to hold on to secure the gold medal he had vowed to win.
"I feel a bit tired, but I'm very happy," said Gordon who at senior level lost the World Championships bronze medal in Berlin last August by just 0.03.
The world leader added: "Coming home on the straight, I actually felt the presence of the Japanese coming on to me. I just didn't know what to do exactly, so I just went ahead and held him off.
"I slowed up a bit too much. I'm satisfied that I got the gold medal."
Gordon added: "I still have the 4x400 and hopefully our team will go there and medal also."
Abe after a never say die performance and PB of 49.46, said: "I felt I had a poor start but I was able to recover. Halfway through the race I knew I needed to push myself and I was happy with my finish.
"I set a goal of doing my personal best which I did and I am pleased with the silver medal.
Another Asian junior title holder and this year's leading high jumper Mutaz Essa Barshim lived up to his reputation much more comfortably when winning with a height of 2.30m.
Barshim whose winning performance was just a centimetre below his best, beat off the challenge of US champion David Smith who cleared a PB 2.24m and Japan's Naoto who produced a season's best 2.21m.
The Qatari winner kept a clean sheet until needing a second attempt at 2.26m a height which Smith after battling gamely, failed to clear.
"I think when I missed at 2.26m it was the best for me because then I started to think about what I was doing," said Barshim. "I got into the mood and made 2.30m on my first jump.
Barshim who then had the bar lifted to what would have been a PB, said: "I'm not very proud of my second and third attempts at 2.32m. The first one though was very close."
Big World leader in Javelin final
Till Woschler with the biggest javelin throw in the world this year, lived up to his pre-Championships billing as the likeliest to win the gold medal.
The 19-year-old German giving it everything with his first attempt, hurled his spear out to a distance of 82.52m to better the world lead of 78.64m he set on home soil in Saarbrucken at the end of May.
It was the first time a German had clinched the title ahead of Japan's Genki Dean who in a close chase for silver, threw a PB 76.44m in round four and Russia's Dmitri Tarabin whose best of 76.42m came in the second.
Dafne Schippers the overnight heptathlon leader maintained her form on the second day to score a heralded victory for the Netherlands with a a score of 5967 points.
Germany's Sara Gambetta although finishing last in the final discipline the 800 where despite the placing she set a PB, claimed second tallying 5770.
Helga Thorsteindottir lying fourth before the final discipline, lifted herself to win the 800 and the valuable points earned moved her into bronze medal position with a score of 5706, just a single point ahead of Estonia's Grete Sadeiko.
The women's long jump with world leader Darya Klishina not included in the Russian team, saw Cuba's Irisdaymi Herrera after taking the lead in in round two improve to a PB gold medal leap of 6.41 in the fifth.
China's Wupin Wang already lying second after clearing 6.21m in the fourth improved to 6.23m with her last attempt. The Ukraine's Marharyta Tverdohlib finished third with 6.20m.
The United States women with fluid baton won the second heat of the 4x100 relay by almost a second and it came as no surprise that Kendrick, Takeia Pinckney, Dezerea Bryant and Ashley Colley, posted a National record of 43.56.
Great Britain a distant second held off Canada with a time of 44.62 with the host nation clinching their place in the final in a time of 44.77.
Germany the fastest 4x100 relay team in the world this year also produced a fluent performance to qualify for Saturday's final in a time of 44.52.
They were followed home by Jamaica who recorded a season's best 44.68 while the Netherlands with 100m bronze medallist Samuel who medalled behind Kendrick in the 200m final later in the evening on the last leg, posting a national record of 44.70.
Nigeria and Australia progressed as fastest losers with season fastest marks of 45.19 and 45.41.
Jamaica won the men's first heat in a world leading time for the year of 39.74 ahead of Trinidad and Tobago for whom Kevin Haynes had an inspirational third leg as the team clocked 39.88.
But that time didn't last very long when the USA squad with an immaculate performance in the next heat went even quicker in 39.69 to hold off the Nigerian quartet which produced a season's best of 39.95.
The third and final heat was a thriller with Germany and Great Britain looking the likeliest qualifiers until Iizuka with a good warm up before the 200 final, running a great final leg for Japan.
His superb finishing speed down the finishing straight clinched them victory by 0.02sec in a season's fastest of 40.04 from the Germans with Great Britain a further 0.01 behind.
However the Brits who messed up their final changeover, made the final as a fastest loser along with Thailand who clocked 40.00 when third behind the USA and Nigeria.
David Martin for the IAAF