Summer McIntosh and Katie Ledecky set up a showdown for the ages at swimming's world championships in Singapore when both stars cruised into the 800m freestyle final on Friday.
American great Ledecky, 28, is the undisputed master in the event, having won the title at the last four Olympics and updating her own world record in May this year.
But McIntosh, 10 years Ledecky's junior, is in the mood to snatch her crown as she looks to join Michael Phelps as the only swimmer to win five individual titles at a single world championships.
The 18-year-old Canadian has already bagged three golds from three events in Singapore and she clocked the third-fastest 800m freestyle time ever in June.
The other nine times on the top 10 all belong to Ledecky but McIntosh's form suggests a changing of the guard could be on the cards.
Ledecky fired the first shots in Friday morning's heats, qualifying for Saturday's final fastest in a time of 8min 14.62sec, with McIntosh third in 8:19.88.
McIntosh said she felt in good shape after winning 200m butterfly gold the previous night, and she had the rest of the day and the following morning to recover before the final.
"I felt a lot better than I thought I was going to this morning," McIntosh said after her heat.
"I've been recovering really well, probably the best I ever have in a big meet like this.
"We're on day six so to feel like this is really promising."
TITANIC TUSSLE
Ledecky made her international breakthrough in the 800m free, winning gold at the 2012 London Olympics at the age of 15.
She went on to dominate the event for more than a decade and showed that she still had plenty to offer in June when she smashed her own world record, which had stood since 2016.
McIntosh also headed to Singapore in red-hot form, breaking three world records in a matter of days at the Canadian trials in June.
McIntosh and Ledecky have already had their first head-to-head in Singapore, with McIntosh coming out on top to win gold in the 400m free.
The Canadian is a relative newcomer to the 800m free but she safely negotiated the heats with the minimum of fuss.
"My goal was just to win my heat to pretty much secure that I'll get a lane for tomorrow night's final and do that with the least amount of energy possible," she said.
"I'm just trying to get through it because I've never really done 800 heats before so I don't know what to expect.
"I'm just glad it's over and done with now."
Australia's Lani Pallister and Italy's Simona Quadarella will also hope to stand on the podium after Saturday's race but all eyes will be on Ledecky and McIntosh in the battle for gold.
"Having all those girls around me will definitely push me to a really good time and I'm really excited to race Katie tomorrow night," said McIntosh.