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The Mule and The Rhino will vie for the final sprint spot in the New Zealand men's track cycling team for the Rio Olympics.
Matt Archibald and Simon van Velthooven are contesting to see who will be reserve to world champion team sprinters Ethan Mitchell, Sam Webster and Eddie Dawkins as they seek to create history as New Zealand's first Games medallists in the discipline.
Depending on how the programme pans out, the winner of the duel might also contest the Keirin or individual sprint.
Each rider's curriculum vitae holds merit.
Archibald (The Mule) earned bronze in the 1km time trial at the Glasgow Commonwealth Games and 2015 world championships.
Van Velthooven (The Rhino) took bronze in the Keirin at the London Olympics and has three podium finishes in the 1km time trial at world championships from 2012-14.
New Zealand can take a maximum of nine male track riders to Rio but five will be shared across the team pursuit and omnium.
Cycling New Zealand sprint coach Anthony Peden said both athletes are capable of fulfilling the support role, but it will come down to who is conditioned best when the final nominations are submitted to the New Zealand Olympic Committee.
"There are five of us that can race team sprint, [individual] sprint and Keirin and only three get to race the team and two for each individual event," van Velthooven said.
"I've got to let my legs do the talking. That keeps me hungry every day in training."
Archibald said he's never 100 percent sure what's happening with the quota system, so the best approach is to train as hard as he can.
"As soon as you start comparing to teammates it gets negative. I just treat every training as an opportunity to get faster.
"It's the status quo that you're racing your best mates for positions. [In taking a reserve] we just need to make sure it is a person who can do everything."
The governing body will take 21 riders abroad to finalise their Games preparations.
Archibald competes in an international track series in Melbourne while van Velthooven races in the United States. Future prospect Zac Williams will gain experience with the incumbent team sprinters and women's rider Natasha Hansen in Germany.
The remaining 14 male and female endurance riders will divide between Australia, the United States and Europe.
The full Rio team will be confirmed in the first week of July.
The travelling riders are:
Sprint: Natasha Hansen (Southland), Matt Archibald (Southland), Eddie Dawkins (Southland), Ethan Mitchell (Auckland), Simon van Velthooven (Manawatu), Sam Webster (Auckland), Zac Williams (Auckland). Coach: Anthony Peden.
Female endurance: Rushlee Buchanan (Waikato), Holly Edmondston (South Canterbury), Lauren Ellis (Mid Canterbury), Alysha Keith (Otago), Jaime Nielsen (Waikato), Racquel Sheath (Waikato), Georgia Williams (Auckland). Coach: Brendon Cameron
Male endurance: Pieter Bulling (Southland), Alex Frame (Canterbury), Aaron Gate (Auckland), Regan Gough (Central Hawkes Bay), Dylan Kennett (South Canterbury), Nick Kergozou (Southland), Hayden Roulston (Mid Canterbury). Coach: Tim Carswell.