Caster Semenya’s strongest opposition on the way to winning Commonwealth gold came from a faulty starter’s gun which left the women contesting the 1500m final struggling to stay warm on the start line.

A deluge of rain before the race soaked the track at the Carrara Stadium and flooded the timing equipment. As organisers struggled to repair the clock and gun, the South African bounced on the spot in an effort to keep her muscles warm.

The 1500m, the final event of the day’s athletics, eventually got under way 10 minutes behind schedule and Semenya was utterly dominant. She assumed a commanding position in the pack before executing her break with 300m to race, overtaking Kenya’s Beatrice Chepkoech, who finished second, with 150m left. Wales’s Melissa Courtney came third in 4min 03.44sec. Already double Olympic 800m champion, it is the first time Semenya has been to a Commonwealth Games and she performed a swan-like celebration after crossing the line in a Games record of 4:00.71.

“As a middle-distance runner I have done enough for my collection but this is for me, country and for the youth, we are inspiring the youth, we just want to show them they can do it,” Semenya said. “It rained so it messed up the clocks so they had to make sure the clock was running. It wasn’t bad for me.”

The 27-year-old will attempt to add the 800m title later this week but is running in the knowledge that a proposed change in rules concerning hyperandrogenic athletes may spell the end of her career.

Semenya has hyperandrogenism, a medical condition most commonly affecting women that is characterised by heightened levels of male sex hormones, including testosterone. The IAAF, athletics’ world governing body, has stated it hopes to have revised rules in place by November which will restrict testosterone levels in female athletes. It could mean Semenya will face a decision on whether to take medication to inhibit her testosterone levels or stop competing at elite level.

The Australian 800m runner Brittany McGowan added fuel to the debate around Semenya’s inclusion by suggesting her times and those of others competing in the same races as the South African should not be compared. “It’s a tough one,” McGowan said. “It’s tough for a lot of women in the 800m, 400m and 1500m at the moment to compare ourselves and be judged by our governing bodies on those times.”

Commonwealth Games 2018 day six: Semenya storms to 1500m gold and more – live! Read more

Scotland’s Eilish McColgan, coached by her mother Liz McColgan, who won gold at the Commonwealth Games in Auckland in 1990, could manage only sixth. “My mum said to me at 600, you need to be going. But the pace was so fast, I was already going,” she said. “I don’t know what more I could have done. I maybe waited too long because those girls are specialists and over the last 100 it takes me longer to get my legs going. I’m gutted because I was so close and it was there.”

Isaac Makwala, the Botswana sprinter who kept the London world championships entertained last summer with a saga around his inclusion, won gold in the 400m. Makwala was barred from competing in the 400m final in London after complaining of an illness but later claimed he had been well enough to compete. The 31-year-old crossed the line in 44.35sec open-mouthed and arms spread in a crucifix position, finishing well clear of his compatriot Baboloki Thebe, who took silver in 45.09, and Jamaica’s Javon Francis in third.

He claimed the Commonwealth title made up for the disappointment of not being allowed to compete in London. “I came here ready for this and everything has been going well since the world championships,” he said.