Finau had played with mixed success as a centre, but, pressed into service in the second row in place of the injured David Hulme, he did the damage to Oldham's defence that set up a Warrington victory.
He struck first within the opening two minutes, striding on to Kelly Shelford's pass for the first try. After Kris Watson and Paul Cullen had also gone over for Warrington, it was Finau's superb long pass that released the winger, Richard Henare, for his first.
Warrington could not shake off Oldham, who scored breakaway tries through Adrian Belle and Mike Neal to keep themselves in touch.
When Martin Crompton went over against his old club after the break, Oldham were only six points behind, but then Finau chimed in again, taking Toa Kohe-Love's pass to score his second.
Kohe-Love soon laid on a second for Henare and the South Pacific theme continued to be the dominant one when Henare succeeded in upstaging Finau by going 85 yards for his hat-trick.
Paul Sculthorpe and Willie Swann then opened the way for Ian Knott, who also kicked five goals. Oldham emphasised just how crucial Finau and Finali's contributions had been by scoring the 12th try of the match through Neal in the closing minute.
Warrington: Knott; Forster, Kohe-Love, Roper, Henare; Shelford, Swann; Jones, Watson, W Stevens, Finau, Cullen, Sculthorpe. Substitutes: Rudd, Mafi, Chambers, Davies.
Oldham: Atcheson; Belle, Topping, Neal, Ranson; Maloney, Crompton; Guy, Burns, Faimalo, Munro, Davidson, Bradbury. Substitutes: P Stevens, Gildart, Nuttall, Crook.
Referee: R Connolly (Wigan).Reuse content