Campbell's 52.06-second swim at the Brisbane Grand Prix on Saturday shaved just one one-hundredth of a second off Britta Steffen's seven-year-old mark but landed a heavy psychological blow to her rivals, including her world champion sister Bronte.
None have come close to German Steffen's time which was set in a now-banned synthetic suit in 2009.
Bronte Campbell is a distant second in the world rankings, her best time of the year more than half a second slower than her older sister's.
Simon Cusack, mentor to both Campbell sisters, was bursting with pride after Cate tore up the Brisbane Aquatic Centre but was also quick to remind her that the world record would mean little on the starting block at Rio.
"While it's really nice to have the mark, it's no guarantee of what's going to happen at the Games," the Brisbane-based 39-year-old told Reuters on Monday.
"Winning a gold medal comes down to one moment in time and not only do you need great preparation, you do sometimes need a little bit of luck on your side," he added.
"When you're living in an Olympic village with people coming from all corners of the globe and eating out of the same food hall you get exposed to a lot of viruses and bacteria.
"So that's why winning a gold at the Olympics is such a tough thing and very often they're not won in world record time. So I've expressed that to Cate," Cusack said.
"She's very, very happy with having that world mark but it doesn't change anything from here on in."
The 24-year-old Campbell is unlikely to need further reminders of how luck can change the game when she appears at her third Olympics.
She won bronzes in the 50m freestyle and 4x100m relay on her 2008 Games debut in Beijing before losing years to illnesses including glandular fever and post-viral fatigue.
At her second Olympics in London, she won gold in the 4x100m freestyle relay but her individual campaign was wrecked by a bout of pancreatitis.
When fully fit, the 2013 world champion has shown she has no peer, however, as witnessed by her breathtaking return to form this year.
