The two medals increased Nigeria’s tally at the championships in Nairobi to three gold and two bronze with one day of competition remaining.
This shot Nigeria to third on the medals table, behind Kenya (5-1-3) and Finland (3-1-0).
Onwuzurike running in lane 3 coasted home in 20.21 seconds ahead of Letsile Tebogo of Botswana (20.38) and South Africa’s Sinesipho Dambile (20.46) who finished with the silver and bronze respectively.
The U.S Collegiate fastest runner in the 200m proved that his rating was no fluke as he made history to win the race in a personal best time.
Onwuzurike thus erased compatriot Francis Obiekwelu’s long-standing record of being the last Nigerian to have won the event since 1996.
Nigeria have by the end of day four of competition won five medals.
These are: gold in 4x400m mixed relay, 400m women, 200m men and bronze medals in javelin men and 200m women.
The championships which started on Tuesday, with competition beginning on Wednesday, will end on Sunday.