The 25-year-old, who became Kenya’s first gold medal winner in the sprints at the 2015 world championships in Beijing, announced he was back to full fitness when he led a magnificient gun-to-finish victory at the Kenya national trials.
Bett clocked 49.14secs, with his twin brother Haron Koech a distant second in 50.68. Willy Mbevi was third in 51.01.
Reigning World 1500m champion Elijah Manangoi was pushed into second place by his training mate and world silver medallist Timothy Cheruiyot in a pulsating race.
“The best man won today,” said Manangoi.
“But I have managed to make the team, and I will go to Australia prepared to add the Commonwealth title to the gold medal I won at the world championships in London last year.”
The absence of David Rudisha in the men’s 800m and the failure by top-ranked Ferguson Rotich to finish the race means Kenya will have a fresh line-up of athletes at the Gold Coast.