An emotional Alice Mills wept tears of joy following her breakthrough win in the women's 100m freestyle while a shattered Libby Lenton shed tears for the opposite reason.

The 18-year-old Mills (53.96 seconds) broke the 54-second barrier for the first time in the glamour event at the world championships trials to become the fourth fastest swimmer in its history.

It was a sweet victory for the Canberra-based Queenslander after being squeezed out of an Olympic berth in the 100m by 0.09s last year.

Mills had kept the hood of her AIS jacket over her head before being announced onto the pool deck and less than a minute later she had stolen the spotlight.

Her coach Shannon Rollason had said pre-race a win would bust open the floodgates for Mills and there is a feeling she is ready to explode on the international scene following a below-par Athens Olympics.

Mills' clubmate Jodie Henry (54.18) surprised herself by finishing second after repeatedly declaring she was no chance of winning an individual berth this week following a disrupted preparation.

The Olympic champion and world record holder's swim will only rub salt into the wound for third-placed Lenton (54.26), who was despondent in her bright pink swimsuit.

Lenton stunned the nation 12 months ago by breaking the world record at the Olympic trials but has since struggled to match those feats.

The 20-year-old failed to make the Olympic final and has now missed out on an individual berth for Montreal in the prized event.

Lenton took the race out hard and was well under world record time after 50m before being overhauled in the last 15m by Mills and then the always fast-finishing Henry.

Brought to you by AAP © 2024 AAP