Wollongong swimmer Emma McKeon broke the Australian record to join her brother Dave in qualifying for the Commonwealth Games in Glasgow later this year.
With a stunning performance on Tuesday night, Emma beat Kylie Palmer's previous Australian record with a time of one minute, 55.68 seconds in the 200 metre freestyle final.
The siblings hugged on the pool deck as Emma celebrated her win.
Dave, a member of the 2012 London Olympics, continued his rise on the international stage, as he led the 400m freestyle final from the outset, finishing in a time of 3.43.90.
"It's pretty exciting, just great to be on the Commonwealth Games team with my brother," 19-year-old Emma said.
"Been training really hard, I knew I could go pretty fast."
The pair recently moved to Brisbane to be coached by Vince Raleigh after years of tutelage from their father, Ron McKeon, in Wollongong.
"He kicked me and Emma out of home," Dave said with a smile after the race in Brisbane.
"This is my home pool now and I wasn't going to let anyone beat me in my home pool."
Dave, 21, had clocked the world's second fastest 400m freestyle time of 2014 - 3.44.95 - to easily be fastest qualifier for Tuesday night's final.
The world No 2-ranked McKeon bombed out at the 2013 world titles in Barcelona after a poor heats showing ensured he missed the final entirely, finishing 12th overall.
"I was spooked last year [at the world titles] but I will be ready this year," McKeon said.
His heat time would have just missed out on a world titles podium finish and was only a second outside his personal best (3:43.71).
Only three Australians have swum faster over 400m - Ian Thorpe (3:40.08), Grant Hackett (3:42.51) and Kieren Perkins (3:43.80).
He edged out junior world champion Mack Horton (3:50.20) and fellow teenager Jordan Harrison (3:50.38) who is recovering from a broken wrist before the final.
Meanwhile, sister Emma, who is ranked in the world top five, impressed before Tuesday night's women's 200m freestyle final.
She (1:58.51) was second fastest in the heats behind Olympic bronze medallist Bronte Barratt (1:58.23) and Brittany Elmslie (1:58.64).