Teenage distance swimmer Jordan Harrison has become the first Australian man to reach a 1500m freestyle final on the world stage since Grant Hackett in 2008.
The 18-year-old went under 15 minutes for only the second time in his career with a superb heat swim to qualify sixth-fastest for Sunday night's (Monday morning AEST) final at the world championships in Barcelona.
Harrison clocked a time of 14 minutes and 58.62 seconds on Saturday, almost half a minute quicker than his heat swim en-route to winning the national title in April.
"For a morning swim that was pretty hard so I'm happy I got under 15," Harrison said.
"I was just going in with the mentality that this is the only race left.
"I wasn't even considering a final. I wanted to bang out a good swim this morning and hopefully that could get me into the final."
The heats were topped by Chinese distance superstar Sun Yang (14:54.65), who paid tribute to the young Australian's effort.
"Jordan did a good job," Sun, the Olympic champion and world record holder, said.
Harrison, trained by Denis Cotterell who also mentored Hackett and Sun, clocked 14:51.02 in the final at national titles in Adelaide becoming the second-fastest 17-year-old ever in the event behind Kieren Perkins.
Harrison has also made the 400 and 800m finals in Barcelona this week and said his first meet at the highest level had been a huge learning experience.
"I think it's pretty mentally tough to stay on it the whole week," he said.
"There's been ups and down when you're feeling pretty flat but I felt good today."
Earlier, Cate Campbell took the first step towards a golden double at the meet as she set a cracking pace in the 50m freestyle heats.
Backing up from her win in the 100m freestyle final, Campbell matched her season-leading time of 24.27 seconds to qualify fastest for Saturday night's 50m semi-finals in Barcelona.
The 21-year-old raced alongside younger sister Bronte, who qualified third-fastest in 24.65 to ensure the siblings will again swim side-by-side in the semis.
Cate's performance was all the more impressive considering she was still feeling the effects of Friday night's win.
"I'm stinging a little bit, I won't deny," Campbell said.
"But I did what I needed to do, got through fairly comfortably so hopefully I can just build on that.
"(The time) is a good sign of not that much sleep and not getting probably as much rest as I would have liked."
Britain's Fran Halsall (24.60) and Dutch Olympic champion Ranomi Kromowidjojo (24.68) were among the other top qualifiers.
Russian Yuliya Efimova produced the swim of the morning as she broke the world record in the heats of the 50m breaststroke.
Efimova clocked 29.78 seconds to shave two tenths of a second off the previous mark set by American Jess Hardy in 2009.
Ashley Delaney (25.36) qualified 13th fastest for the 50m backstroke semis while Samantha Marshall (31.49) was 15th qualifier from the women's 50m breaststroke heats.
