The 4x100m Olympic bronze medallist in Paris 2024 crossed the line in 6.49 for his second personal best in as many international competitions ahead of Australia's Lachlan Kennedy on 6.50 and South Africa's Akani Simbine who clocked 6.54 for bronze.
Azu stormed out of the blocks to beat Kennedy, who had set a world leading time of 6.43 in January, and roared in delight when his name appeared on the jumbo screens after Kennedy’s had appeared first.
It has been a stunning year for 23-year-old Azu who remains unbeaten over the distance after retaining his British indoor title before winning the European crown in Apeldoorn last month.
Hunter Bell, Anning and Gourley through to finals
In the women's 1500m Georgia Hunter Bell put her recent European indoor championship woes behind her to reach Sunday’s world final.
The 31-year-old was in medal contention in Apeldoorn but faded on the final lap after struggling with an ear infection and finished fourth behind teammate Revee Walcott-Nolan.
However inside a bustling Nanjing Cube on Friday Hunter Bell took the lead with two laps to go and didn't let slip, storming past the finishing line ahead of Australia's Georgia Griffith to qualify first in a time of 4:09.21.
"I think being an athlete is all about coming back when things go wrong," she explained. "I've had a really good two weeks (training in Dubai) and it’s just about being mentally strong.
"I was definitely pretty upset (after the Europeans), definitely the toughest step so far in my career. I know that there will be tough times but that was my first really big one.
"(Today) is just about getting through safely and qualifying for Sunday. I’m really happy. I can actually hear out of left ear, which is nice!"
Hunter Bell will be the sole British representative in the final after Walcott-Nolan struggled to chase down the leading pack in her heat and agonisingly crossed the line fifth, later admitting that she is "gutted" to miss out.
"I don’t know how to describe that," she explained. "I got clipped, lost contact with the group and I just couldn’t bring it back which is really disappointing.
"I am in a lot better shape than that. I knew it would be tough to make the final today, but I’m really gutted that I didn’t.
"Preparations have gone really well, the last couple of weeks have been solid, I’ve been in a really good mindset so to not pull it out of bag today is disappointing."
In the men's, Neil Gourley booked his place in Sunday's 1500m final by finishing first in a time of 3:36.60 but teammate Adam Fogg misses out after crossing the line sixth.
Fogg later admitted feeling that despite "running all-out" to catch-up he felt he was "going backwards".
Gourley will face stiff competition from Norway's Jakob Ingebrigtsen who stormed around the final lap of his heat as he bids to make history in China.
The double Olympic and world champion has never won a world indoor title and is competing in both the 1500m and 3000m in Nanjing.
If he tops the podium in both events he will emulate the achievement of Haile Gebrselassie who was the last man to win the indoor middle distance double in 1999.
Elsewhere Amber Anning reached the final of the women's 400m on Saturday with 50.79, the quickest time in the heats, as she bids for her first world title.
"It felt good, it felt smooth. I wanted to run a 50-point to set me up nicely for the final tomorrow and get me a good lane so it felt really smooth and the track feels fast," she said.
"I’ve prayed a lot, worked with the coach and put my head down and trained hard for this."