Guliyev's win may not have been following the script the organisers wished for after two-time doping cheat Justin Gatlin's win.
Guliyev's win may not have been following the script the organisers wished for after two-time doping cheat Justin Gatlin's win in the 100m upset superstar Usain Bolt's farewell.
Normal order was restored, however, in the night's other two finals with the United States going one-two in both.
Christian Taylor won his third world title in the triple jump with his great rival Will Claye taking silver just as he has done in two successive Olympic Games.
However, Olympic 400m hurdles champion Dalilah Muhammad was unable to add the world gold as she was run out of first by compatriot Kori Carter, the 25-year-old previously regarded as a journeywoman.
Van Niekerk, who had won the 400m earlier in the week, took a swipe at people who he feels have belittled his achievements.
"There are many people who don't think I deserve this," said the 25-year-old, who produced the performance of the Olympics last year breaking the 400m world record in winning gold.
"I work just as hard as every other competitor. I don't think I got the respect I deserved after the 400m (winning the world gold) but it's only the beginning and I will show my dominance."
As Guliyev's win was confirmed after a thrilling finish to the 200m, some boos rang out and thousands of spectators couldn't make the exit quickly enough.
The 27-year-old Azerbaijan-born sprinter, who became a Turkish citizen in 2011, then draped himself in both the Turkish and Azeri flags as he performed his lap of honour.
"It's not a shock. I wanted to win and this year I thought it was possible and I made it," said Guliyev. "Yes I believed in myself."
Taylor won well enough but the threatened assault on Jonathan Edwards's 22-year-old world record never materialised.
He did show his champion's mentality in twice coming back to better Claye's marks and leave his 26-year-old rival to add another silver to his ever growing collection in his trophy cabinet.
"Will makes it tough every single time," said 27-year-old Taylor who added he will move up to the 400m only when he breaks the world record and has a permanent reminder of the 18.30m he needs to do so...on his wrist.
"I have this watch from my sponsor with 18.30 on it. I will try to fight, I will get this number," he said.
"The record is still on. I am still motivated to break that record."
Carter, who is managed by American athletics legend Allyson Felix's brother Wes, more than justified her decision to opt for athletics ahead of her first love for football.
"When you work so hard and sacrifice so much for something, for it to pay off in the end is so satisfying," said Carter.
"It's a surreal experience right now. Me and my coach (Bobby Kersee), our whole goal and focus was to get on the podium this year, it's what we've been committed to."
Caster Semenya looked to have more than recovered from her exertions in the 1500 metres where she took bronze as the two-time world champion eased through her 800m heat to reach Friday's semis.