Abdul Hakim Sani Brown overtook Jamaican sprinting superstar Usain Bolt to become the youngest-ever men's 200 meters finalist at the world athletics championships on Wednesday.

Born to a Ghanaian father and Japanese mother, Sani Brown, who will be 18 years and 157 days on Thursday when the final takes place, improved Bolt's previous record of 18 years and 355 days set at the 2005 championships in Helsinki.

He also becomes the first Japanese in 14 years to advance to the men's 200 meters final, finishing second in his semifinal heat by clocking 20.43 seconds, 0.11 second slower than his personal best of 20.32.

"I got lucky. I saw that no one was closing in behind me in the latter half so I thought I had a chance," said Sani Brown.

"I tried to focus on the first 100 meters. I found my rhythm early on which was good. I hope to raise my level a notch and put on a good race (in the final). I want to dive over the finish line for any chance for a medal," he said.

Japanese compatriot Shota Iizuka finished fifth in his heat in 20.62 and failed to qualify for the eight-man final, which includes South Africa's Wayne Van Niekerk, who will be bidding for a 200-400 double after winning the 400 meters on Tuesday.

Sani Brown is the first Japanese since Shingo Suetsugu in 2003 to make the start list for the 200 final. Suetsugu won bronze in the meet in Paris that year with a time of 20.38.

Sani Brown missed out on a spot in the 200 final in the last championships in 2015, finishing fifth in the semis.