The ultimate dilemma: Australian selectors must choose between the Campbell sisters tonight.

It was never meant to be an easy decision, but it looked like it was always going to be Cate.

Cate Campbell, a darling of Australian swimming, was thought to be a lock to bring home the gold in the women’s 4×100 medley relay on Tuesday night. She would snag the freestyle leg, for before then, she had been swimming the fastest.

But on Monday night, younger sister Bronte slammed the wall 0.42 seconds ahead of her to take gold in the 100m freestyle, throwing selectors into a bit of a spin: Which Campbell sister do they take to the relay?

“That was incredibly surprising. I don’t know how that happened but I am glad it did,” Bronte said after the race.

“I was 100 per cent going out there thinking ‘this was my last race for the meet and the year. I was saying ‘this is my last warm-up, this is my last suit’ before the race. But I might have to do the relay now. We will see how we go.”

Mamamia Out Loud on the only thing people are talking about regarding the Commonwealth Games. Post continues after audio.

Cate, meanwhile, was at gracious as ever.

“I am so thrilled for Bronte to get a massive win in front of a home crowd. It is never easy being the second Campbell and she is number one now and I am thrilled for her,” she said.

“It makes the pain of coming second just that little bit sweeter when the number one is next to a Campbell.”

In an interview with, Australian swim coach Jacco Verhaeren says neither Bronte or Cate were consulted about the decision on who would swim.

“There’s no doubt they both deserve it, but we need to make a call for what’s best for the team,” Verhaeren told the news outlet.

He said the decision had in fact already been made, but the team would not reveal who was swimming until an hour before the race.

The relay is set to take place at the Gold Coast Aquatic Centre at 9.40pm on Tuesday night.