Serena Williams' great advice for Aussie swimmer sisters Cate and Bronte Campbell.

Over the weekend a couple of Aussie sisters made history at the Rio Olympics.

Aside from breaking the standing world record as part of the 4x100m freestyle relay team, Cate and Bronte Campbell also became the first Australian sisters to win gold in the same event.

It was a dream come true 15 years in the making for the Brisbane siblings to stand side-by-side on the poolside podium, but later in the week the two will likely go head-to-head inthe 50m and 100m freestyle finals.

World tennis number one Serena Williams is no stranger to the pangs of sibling rivalry in the sporting arena.

Having downed her sister Venus in eight grand slam tournaments, she knows all too well that sometimes winning has to come at a family member’s expense.

Mamamia founder Mia Freedman speaks with Leisel Jones about life after Olympic glory:

Fresh from the court after ending Aussie Daria Gavrilova’s Olympic dream, the gold medallist doled out some golden advice for the Campbell sisters when a journalist told her about them.

“Are they competing against each other? What sport?,” Williams asked.

Our first gold

A photo posted by Serena Williams (@serenawilliams) on Aug 4, 2016 at 4:57pm PDT

“Oh that’s cool. Well I hope they can get gold and silver — I always root for sisters. As long as there are no Americans in there. They’ve just got to leave it all out in the pool and once they get out of the pool, family first.”

Cate and Bronte — who are 24 and 22, respectively — began swimming together when they were just nine and seven, getting up at 6.30am to walk to the swimming pool together.

“This has been a dream for so long and it’s come true,” their mother Jenny told the Seven Network after their joint win.

“It almost seems unbelievable that I have two daughters who stood at the top of the podium at the [Olympics], doing what they used to talk about doing 15 years ago.”

Older sister Cate is tipped to win the individual events, but we get the impression Bronte will be over the moon for her.

Good luck guys!

Meanwhile, these are the other female Aussie Olympians we’ll be keeping an eye on:

Feature image: Instagram