Caleb Ndiku added a second global title to his name this year when dominating the 1500 final from gun-to-tape and winning in a personal best 3:37.30.
The eighth Kenyan title winner and World Junior Cross Country champion did it in a confident style leading through 400 in 55.89, passing 800 in 1:55.33 and completing the third split in 2:56.46 before going into overdrive.
Ndiku showed no signs of strain after having been at the point throughout, and after his speedy break, Abderrahmane Anou, and pre-race favourite Mohammed Al-Garni the silver and bronze medallists had their own private battle.
The Algerian in a very tense finish clocked 3:38.86 to beat the Qatari by a narrow 0.05.
Japan-based Ndiku who covered the final circuit in 55.23, said: "I know I have lots of endurance and I know the other guys are very good in speed, more than me, so that’s why I started to run from the front all the way.
"My coaches told me I must have hope to win. That’s also why I started to run in front so that at the end of it, if somebody caught me, then I would get silver, but they were not able to.
Ndiku looking to the future added: "I am now thinking about European grand prix races next month. I go back and train a bit, and then I’ll be running the 1500 metres and the 3000 metres.
Moroccan-born Al Garni, admitted: "I was looking for something better than third place but the Kenyan runner was very strong and has more experience at this level than me.
"I still have a long way to go if I want to become the best in the world but I will continue to train and get better."
Kirani James wins gold but not that easy!
Kirani James duly won the 400 metres gold medal but the outstanding Grenadian who finished runner up two years ago, found himself with a battle on his hands down the home straight with Marcel Deak Nagy.
James went off very quickly and it looked as he blazed down the backstraight, that last year's World Youth champion was poised to add to his medal tally after his great start.
But he found Nagy who didn't expect to win a medal but surprised everyone when winning his semi final again in great form and the Hungarian coming into the home straight came alongside the undisputed favourite.
James held his form but in a close call he won by only 0.20sec in 45.89 with US champion Errol Nolan third in 46.36.
"I feel good with the win, but the time wasn't impressive to me or to the fans or anybody," he admitted. "I didn't feel any pressure but my legs weren't going for me."
Lavric adds junior gold to youth title
Mirela Lavric running a perfect tactical race comfortably defended her 800 title to thwart the hopes of African rivals Cherono Koech and Annet Negesa.
Lavric won in a time of 2:01.85 to beat off the challenge of the Kenyan last year's World Youth gold medallist who clocked 2:02.29 and Negesa from Uganda who has surpassed her expectations at the bi-annual Championships and recorded 2:02.51.
The Romanian winner was more than happy to follow the fast pace set by Negese who stormed through the first 400m in 57.79 but was never able to break her two opponents despite the speedy pace.
Lavric stormed into the lead coming off the bend as Koech and Negesa with Cuba's Rose Mary Almanza hot on their heels, fought a tense battle for the podium places.
Lavric the 2007 Youth gold medallist who felt the pressure from Koech in the home stretch, said: "This is my third time being a world champion so I'm very happy with the win this being my last junior competition.
"It was a very hard race, she pushed me. I am not happy with the time, I felt I could have done better."
Pedersen all the way
Isabella Pedersen a year after being crowned World Youth 100m hurdles champion in Bressanone added another coveted gold medal to her collection with a thrilling win in the Stade de Moncton.
Pedersen did it in great style smashing the Norwegian record with a superb time and second fastest in the world this season of 13.30 when holding off the challenge of Jenna Pletsch by 0.05sec and her German teammate Miriam Hehl who clocked 13.46 a time she shared with the unlucky fourth finisher Danielle Williams of Jamaica.
Pletsch and Hehl were fastest out of the blocks but by the third hurdle Pedersen had hauled them in and although she clattered the next barrier it didn't affect her stride pattern.
The 18-year-old held her form as Pletsch produced a ferocious turn of pace coming off the last hurdle, winning her country's second medal in the event in succession to Christina Vukicevic's silver four years ago.
Bahamian win in women's 400
Margaret Etim the world 400 leader this year went off very quickly and going down the back straight it seemed she was on target to succeed fellow Nigerian Sade Abugun as world champion.
But victory with a surging charge went to Bahamian Shaunnae Miller who took charge of the race to win in 52.52 as Etim in the final 50m began limping and finished in 53.05.
The pair were in a class of their own as they initially battled in the home stretch until Etim suddenly began to slow but managed to hold off Romania's Bianca Razor, third in 53.17.
Purity Kirui sealed the fourth successive Kenyan victory in the 3000 steeplechase keeping the gold medal in her country's possession since it was introduced to the Championships programme.
Kirui with a speedy final lap won in 9:36.34, with a plucky Birtukan Adamu after being overtaken by the second Kenyan representative Lucia Muangi with 250m remaining, fighting back to win silver for Ethiopia.
The pair as did the winner ran the fastest time of their careers finishing in 9:43.23 and 9:43.71 in a race which featured five national records and one other personal best.
Kirui throughout kept herself out of trouble as several of her rivals in the wet conditions suffered falls at the water jump, three of the field falling foul of the obstacle on the first lap.
Double celebration for Cuba
Dailenys Alcantara may have produced only one big real leap by her own world class standards of 14.09m, but it was long enough to see her retain her triple jump crown.
The 18-year-old Cuban who has a best this year of 14.34m unleashed the winning effort in the third round for a very comfortable victory ahead of Laura Samuel and Lina Deng.
The British silver medallist achieved a national record of 13.75m with her fourth attempt while China's Deng recorded a personal best with her third round effort of 13.72m.
Yaime Perez on a good night in the field for Cuba captured its first ever discus gold medal with a third round effort of 56.01 to thwart the challenges of Erin Pendleton and Yuliya Kurylo.
Perez had three throws over 50m while the American runner-up who led in the first round with 53.87m improved to 54.96m with her last attempt.
Kurylo of the Ukraine produced her best effot in round three of 53.96m to become the first Ukrainian to ever medal at the championships.
Ivakin takes Pole Vault
Anton Ivakin equalling this summer's World leading mark of 5.50m became the fourth Russian pole vaulter to lift the gold medal in the last five years.
Ivakin who gradually ground down the opposition won ahead of Italy's Claudio Stecchi who cleared a personal best of 5.40m as did Great Britain's bronze medallist Andrew Sutcliffe with a vault of 4.35.
Ivakin won a mind game ahead of Stecchi when the pair with one failure each at 5.45m, passed and moved to 5.50 which the Russian got over at his second attempt.
200m semi finals
Jodie Williams remains on course to adding another gold medal to the 100 metre title she won on Wednesday with another confident victory in her 200 semi final.
Williams the world leader over the distance had an early opportunity to weigh up personally other medal contenders Jamile Samuel and Ashton Purvis who placed third and fourth in the 100 final.
The Briton was fully tested winning by 0.01sec as the Dutch runner-up set a National record of 23.21 while the USA's Purvis looking as lethargic as she did in the first round, clocked 23.48 but went through as a fastest loser to Friday's final.
Last year's double World Youth sprint champion, said of Samuel: "I could see she was running very strong in the heats and she was going to be tough so I just needed to qualify by having a competition with myself and have confidence going into the final.
"It would be amazing to win both the 100 metres and 200 metres to prove that last year was not a fluke. The race was close and I expect the race this year to be close too.
“I’m absolutely shattered and I’m going straight to bed when I get in and I’ll sleep all day tomorrow,” added the 16-year-old. “I was coming round the bend and they were pushing me, but I just needed to get there for myself to have the confidence going into the final."
Allison Peter denied last year's World Youth gold medal although clocking the same time as Williams on that occasion where Purvis was bronze medallist, cruised to victory in her semi.
The US Virgin Islander put in a kick coming into the home straight to win by 0.18sec from Japan's Kana Ichikawa with Canada's Crystal Emmanuel setting a PB 23.96 for third.
The USA's Stormy Kendrick blasted out of her blocks to take the third and final semi then coming into the home straight powered a little harder to win in a PB 23.28.
The British runner-up Emily Diamond also went through by right also recording a PB 23.47 with third placed Kai Selvon also making the cut in 23.51.
The first round disqualification of Dexter Lee and the absence of the USA's Charles Silmon and Frenchman Jimmy Vicaut who finished behind him in the 100m final, has made tomorrow night's 200 final a very open race.
World leader Shota IIuka looks the best bet, the Japanese pulling back a slight deficit coming off the final bend to win his semi final in 20.93 comfortably from the Czech Republic's Pavel Maslak (21.07).
"I’m really happy that I won that race," he said. "At one point coming down the home stretch, it looked like everybody was even and it was a challenge because it was hard to tell where the other competitors were."
IIuka aiming to win his country's first ever sprint medal, added: "I’ll just continue to do the same thing and I’ll never give up - just do the same thing that I did in this race."
Aliaksandr Linnik showed he is running into top shape at the right time when with a dominant run he lowered the Belarusian record to 20.81 with the wind exactly on the legal limit. Trinidad's Moriba Morain finished runner up in a PB 21.03.
Canada's Aaron Brown thrilled home spectators when snatching second place in the opening semi behind Wayde Van Niekirk the winner by 0.07sec in a windy 21.05.
Brown made it by the skin of his teeth progressing after a photo-finish and sharing the same time as the Oliver Bradwell of 21.12.
The men's javelin which also had a delayed start saw three contestants automatically better the 71.50m standard and all were competing in the first group.
Germany's world leader Till Woschler belted out a first round effort of 72.78m, Zigismunds Sirmais of Latvia threw the furthest of 77.97m a personal best with his second attempt while Genki Dean got over the required distance with his final attempt of 72.20m.
Heptathletes concluded their first day and after four events Dafne Schippers of the Netherlands was holding the lead at 3535 points her impressive 23.41 200m run opening a gap with the rest of the field. Germany's Sara Gambetta held on for second overnight at 3471 points with American Alex Gochenour third at 3294 points.
David Martin for the IAAF