The cutthroat nature of the Pan Pacific championships claimed some big names early on the Gold Coast on Thursday.
Australia's Commonwealth Games gold medallist Emma McKeon and reigning world champion Missy Franklin provided the first shocks of the opening morning of the four-day Pan Pacs, failing to qualify for Thursday night's women's 200m freestyle final.
Under Pan Pacs' rules, only two entrants from each country can qualify for a final.
McKeon clocked one minute 57.87 seconds to be sixth fastest in the heats but was slower than compatriots Melanie Schlanger (1:57.16) and fellow veteran Bronte Barratt (1:57.65).
Franklin - a last-minute entry after battling back spasms - was fourth fastest (1:57.63) but was slower than compatriots Katie Ledecky (top qualifier, 1:56.45) and Shannon Vreeland (1:57.40).
In another anti-climax, Olympic great Michael Phelps did not appear on opening day action, opting not to contest the 200m freestyle and 100m backstroke.
Australian head coach Jacco Verhaeren felt for McKeon, who clocked a time two seconds slower than her Games record 1:55.57 at Glasgow.
"Of course she was disappointed but she is young and on a learning curve," he said.
"For her it's a good lesson."
In the men's 200m freestyle, Australia's world No 1-ranked Thomas Fraser-Holmes (1:46.95) knocked over American legend Ryan Lochte (1:47.35) in his heat to be third fastest behind Japan's Kosuke Hagino.
Lochte qualified for the final along with Australia's Cameron McEvoy (1:47.08).
In the women's 100m backstroke, Franklin (1:00.60, third fastest) recovered from her 200m shock to make the final but still could not match Australia's Emily Seebohm (first, 59.72) and Belinda Hocking (second, 1:00.46).
"There is still some discomfort but it [back] is getting much, much better day by day," Franklin said afterwards. - AAP