Kiwi Erika Fairweather is in the the medal hunt for the women's 400m freestyle, after qualifying third fastest with a time of 4m 02.55s.
Fairweather, 20, was in heat two, along with Canadian former world recordholder Summer McIntosh, as the duo went stroke for stroke, until the Kiwi pulled away to make a big statement before the final.
"Having any of the girls in the race, it's good to gauge off where you are and she was the perfect person to do that with today," she said. "I knew I had to be fast this morning to put myself in a good position for the final."
In the third and final heat, Tokyo gold medallist Ariarne Titmus and Rio gold medallist Katie Ledecky were in a battle of their own, but American Ledecky took the top qualifying spot with 4m 02:19s, with Aussie Titmus (4m 02.46s) second.
Fairweather, the current world champion, will contest Saturday's heavily anticipated final from the middle lanes — a huge advantage for a showdown world media are dubbing 'the race of the century'.
The Dunedin swimmer is under no illusion over the task she faces against Ledecky, Titmus and McIntosh, who are the favourites for a podium finish, but Fairweather is ready to assert herself into the heavyweight mix.
"I haven't made my presence unknown," she said. "Who knows what will happen tonight.
"I'm all for shaking things up and I'll give it my best go!"
This is not Fairweather's first Olympic final. At Tokyo, she stunned herself in the heats by qualifying with the fourth-fastest time and a new New Zealand record. She eventually finished eighth in the final
"In Tokyo, I was in an inexperienced rookie," she said. "I have a lot more experience and I have a bit more age behind me — I'm really excited about it!
"It's a lot of recovery now. I'll get in the pool and have a swim down, get to the village and have a nap. Nothing too complicated."
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