In her first trip to the Games at the tender age of 16, Cate captured her only individual medal - a bronze in the 50 free - and also helped the Aussies take bronze in the 4x100 free relay. But she didn't even make the final in the 100 free at Beijing in 2008.

Four years ago in London, Cate was stricken by pancreatitis and had to withdraw from the 100 free. She managed to compete in the 50 but was eliminated in the semifinals.

The highlight was being part of the gold medal-winning team in the 4x100 free relay, an event the Aussies are again favored to win in Rio - especially with Bronte now part of the mix.

"I'm almost more excited to race with Bronte in the 4x100 freestyle relay," Cate said. "That will be a really great night."

Bronte agreed.

"We've always really enjoyed racing together against the rest of the world, not necessarily against each other," she said.

The younger sister also was eliminated in the semifinals of the 50 free at London, but Bronte really began to carve out her own niche at last year's world championships in Kazan. She swept the 50 and 100 free, and joined Cate on the winning 4x100 free relay squad.

Not surprisingly, Bronte isn't conceding anything to her older sibling.

"It's all about what happens at the final, who's the fastest on that night," Bronte said.

"Cate is swimming well. I see her training every day. I know what she's capable of. Breaking a world record is an amazing thing. I'm really proud of her for doing it - but it doesn't really change anything for me."

Cate insisted she is merely focused on herself, not what her little sister is doing.

"No one is going to be more upset if I don't perform than myself," the older sister said.

"I can't speak for anyone else on the team, but it's a very individual and a very selfish sport.