Two of China's top athletes withdrew at the last moment from the day's A Groups, but China won one of them regardless - the men's 81kg.

China then claimed a bronze medal in the men's 89kg, which was won by the Tokyo 96kg silver medallist Keydomar Vallenilla, from Venezuela, with a career-best 175-210-385kg at this weight.

"I’m so pleased with this," he said, clutching his gold medal. 

"This is the first (world title) for Venezuela."

Vallenilla’s best clean and jerk was 10kg lower than Nasar’s, but the Bulgarian was already out of the running on total because he failed with all three of his snatch attempts.

He had prepared for competing in the world's fifth highest capital city by training for 40 days at mid-altitude in Bulgaria but, he said, he had been badly affected by the recent death of a close friend.

Nasar, who was 18 last week, is one of the most remarkable young talents in world weightlifting.

He made 212kg with his first clean and jerk before failing with a junior world record attempt at 217kg.

Up he went to 218kg to go for the senior world record held by the Italian Antonino Pizzolato - who was not fit to compete here - then up again to 219kg and finally to 220kg.

Why so high, when 218kg would have been enough?

"I have lifted 225kg in training many times, and I went all or nothing," he said.

He made the lift and took the clean and jerk gold ahead of China's Liu Huanhua on 215kg and Colombia's Brayan Rodallegas on 211kg.

Rodallegas was third in snatch and clean and jerk, and second overall on 170-211-381, the same total as bronze medallist Liu, who was well back in the snatch on 166kg but made all three clean and jerks.

Liu's final effort at 215kg knocked Kianoush Rostami off the podium on total.

Rostami, the Iranian who won at 85kg at the Rio 2016 Olympic Games, took a silver medal in the snatch and finished fourth on total with 174-206-380.

He had failed to qualify for Tokyo because of injury and a missed entry deadline, and said before competition that he was feeling good after two months of intense training.

Afterwards he said he was "pleased for my country and myself" and he would go away to plan for his next move, which is likely to be the Asian Championships in Korea in May.

Cristiano Ficco became the third Italian of the Championships to bomb out, after Mirko Zanni and Lucrezia Magistris, when he failed with all his snatch attempts.

China's Li Dayin won the men's 81kg.

Rejepbay Rejepov from Turkmenistan earned a huge cheer from the crowd when he went for double glory on his final attempt, a clean and jerk world record of 209kg that would hav given him victory on total.

Rejepov cleaned it and briefly looked as though he could complete the lift, but he failed and slammed the platform in frustration.

Li, who said he will be going up to the Olympic weight category of 89kg, had a lead of 7kg after the snatch after making 171kg, which is 4kg below his own world record.

Li, 24, missed his second clean and jerk at 201kg but made it at the next attempt and was 14kg clear.

Rejepov succeeded at 202kg to secure the clean and jerk gold but could not make another 7kg leap.

Colombia made another visit to the podium when Andres Caicedo, who was 10th in the snatch, made 197kg to take the clean and jerk bronze.

The snatch bronze medallist Kim Woo Jae, from South Korea, looked happier than any of his higher-placed rivals when he made 162-195-357 for third place on total.

Of 23 lifters in the A and B Groups, only Li and Rejepov made their entry totals, and once more there were more no-lifts than good lifts in the A Group.