Australian swimming’s rising star Ariarne Titmus, dubbed The Terminator, showed her killer instinct to back up from her shock 200m freestyle win and defend her 400m national title at the Gold Coast Commonwealth Games swim trials on Thursday night.

Titmus, 17, clocked 4 minutes, 02.36 seconds to win by more than five seconds and eclipse her own Australian record set in December.

Booking her second event for the Games in as many nights, the 17-year-old Titmus showed no mercy to the 400m field — much like her coach Dean Boxall’s approach poolside.

“Some of the things he says aren’t quite appropriate [to share publicly],” Brisbane-based Tasmanian Titmus laughed.

“But he always says if I get better he has to push harder, so it’s been tough.

“He is always on my back. There is never a moment I can relax — I always have to be on.”

And while Titmus notes her coaches style of teaching isn’t for everyone, she says it makes her mentally tough.

“He pushes my buttons sometimes. A lot of people couldn’t handle it but it keeps me mentally tough for racing,” she said.

“I know he is only trying to help me and that he believes in me so much.”

That toughness showed when she upset Olympic bronze medallist Emma McKeon in the 200m medal race in the trials’ first major boilover on Wednesday’s opening night.

Now she has a rare 200m-400m-800m national sweep in her sights.

“Dean was saying it has been a long time since someone has won the 200m, 400m, and 800m at a national championship – it’s real exciting,” Titmus said.

Kyle Chalmers no one-hit wonder

Kyle Chalmers has dismissed fears that he is a ‘one-hit wonder’ by claiming a maiden 100m freestyle title. Photo: Getty

Any doubts that Olympic champion Kyle Chalmers had of being a flash in the pan were quickly dismissed when he claimed a maiden 100  metre freestyle national crown at the Gold Coast Commonwealth Games swim trials on Thursday night.

After clinching 200m gold on Wednesday, Chalmers backed up to clock an impressive 48.16 seconds in the 100m final ahead of young gun Jack Cartwright with defending champion Cameron McEvoy third.

Chalmers admitted he had heard poolside rumours ahead of his comeback meet that he may be a “one-hit wonder” after his shock Rio Olympic 100m breakthrough win.

The 19-year-old was returning from a 2017 sabbatical to adjust to life as an Olympic champ and opt for surgery to correct a heart condition.

“It’s been a rough couple of years since Rio,” Chalmers said.

“I am just glad I can still prove to myself I can do it, that I am not that one-hit wonder.”

As tough as it was, Chalmers now backed himself to pull off the 100m-200m double at April’s Games.

“I was hurting, but now I know can do it I can work on backing up at the Commonwealth Games,” he said.

Asked if he could go faster at the Gold Coast Games, Chalmers said ominously: “Absolutely, I am still in a building phase.”

Cate Campbell after winning the women’s 100m freestyle final. Photo: Getty

Earlier, Cate Campbell, who said she had genuine nerves about making the Commonwealth Games team after her Olympic misfire in 2016, won the women’s 100m freestyle final in 52.37 seconds to equal the world-leading time she set in January.

“I’m just so relieved to be on the team. You can never take these things for granted,” she said.

“You know everyone says you are a sure thing but I was a sure thing to win an Olympic gold medal as well and look what happened there.

“It’s hard to stand up and perform when it really counts and I’m proud I did tonight.”

Campbell finished ahead of sister Bronte (52.96) and Emma McKeon (53.49).