The game's timing is opportune.
Last week, the Phoenix were rocking — after consecutive heavy defeats — but have righted the ship since, with an impressive 4-1 victory over second-placed Western United last Saturday before a 1-0 win over Perth Glory on Wednesday.
"The result against Western United was huge for us," said Sail. "It would have been a slippery slope downwards had we not picked up results in the last couple [of games]."
After impressing last season, Sail has gone to another level this campaign. He has been a strong presence behind a backline that has varied in personnel and experience, with the added responsibility of captaincy since Alex Rufer's knee injury.
Sail's statistics have been spoiled by some heavy defeats, but he has been superb when it matters most, fronting up with a string of crucial interventions in the tight games.
The 26-year-old has built a strong understanding with English centre back Scott Wootton since the visa player arrived in January.
"He's been outstanding — he's the best goalkeeper in the league from what I've seen," said Wootton. "The biggest compliment I can give Oli — and I've said this to him — is that there is never any fuss.
"You see other keepers make camera saves or little spillages. With Oli, there are never any spillages, and when he has to [parry], it's always wide, safe and away. That's a huge attribute to have as a goalkeeper. He pulls out 'worldies', he can kick the ball well, he's a good communicator but he's as safe as houses, and that's one of the biggest attributes you can have as a keeper."
Sail's composure will be tested today against a Mariners team who put five goals past the Phoenix 12 days ago.
"We owe them one," said Sail. "That wasn't a true reflection of where we are at as a team. [Wellington] is a difficult place to play, when the wind is howling and they get off the plane and don't want to be here. We're going to make it as horrible as we can."
Phoenix coach Ufuk Talay confirmed that right back Callan Elliott is out with a hamstring strain, though forward David Ball will play, despite being in a moon boot for most of the week.
Adjusting to a large crowd — with around 15,000 expected — and the resultant hype can be tough but Talay expects it to be a positive force.
"That's the discussion we had with the players," said Talay. "I want the players to enjoy their time while we're here and the best way of enjoying it is getting the result."