Popyrin, a late replacement in the squad following injury to Thanasi Kokkinakis, rose to the occasion when captain Lleyton Hewitt thrust him into his first Davis Cup tie for two years in the semi-final against Finland.
But after overcoming almost crippling nerves to win that rubber against the huge young talent Otto Virtanen on Friday, Hewitt had no hesitation about throwing him into Sunday's (Monday AEDT) opening singles of the final against Italy's Matteo Arnaldi at a teeming Palacio de Deportes Martin Carpena.
It looks a tough one to call with world No.44 Arnaldi ranked only four places behind Sydneysider Popyrin and with the pair level at 1-1 in their head-to-heads this year, with Popyrin beating the Italian in the semi-final en route to his second ATP tour title in Croatia in July.
Arnaldi was left hugely deflated after his defeat in the quarter-final against Dutchman Botic van der Zandschulp, but has been given another chance with the higher-ranked Lorenzo Musetti struggling for fitness after his semi-final singles loss.Â
The second rubber will, as expected, feature the respective national No.1s, Aussie Alex de Minaur and Italy's Jannik Sinner, who was presumably still on a dizzy high after beating Serbian great Novak Djokovic - not once but twice in the space of four-and-a-half hours - in Saturday's semi-final.
More pressure is heaped on Popyrin, knowing that world No.4 Sinner has a perfect 5-0 record against No.12 de Minaur in a match-up that bodes ill for Australia.
If the final comes down to a deciding doubles, Australia's 2022 Wimbledon champions Max Purcell and Matt Ebden are pencilled in to face Simone Bolelli and Lorenzo Sonego, but, fitness permitting, Sinner will again almost certainly be parachuted in to replace Bolelli should that happen.
So far this week, Sinner has played singles and doubles in both the quarter-final and semi-finals, winning all four rubbers.
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