Entering Friday evening's game in sixth place, the congested playoff picture meant that City were able to supplant Adelaide United on goal difference by the time the 90 minutes were concluded, throwing down the gauntlet to their top-six rivals ahead of their weekend fixtures.
Frustrated by a resolute Phoenix backline throughout the opening stanza, Aurelio Vidmar's side finally found a way through in the 51st minute through Tilio, who met a pass from Andreas Kuen in stride and lashed it past Alby Kelly-Heald.
The home side stung to life after going behind, keeper Patrick Beach was forced into one of the best saves in league history to keep City ahead in the 68th minute, somehow reacting in time to stick a paw out and deny a bullet close-range header from Corban Piper.
Though a more respectable scoreline than their 6-1 drubbing at the hands of Kiwi rivals Auckland FC the week prior, the result added to the disquiet swirling around Wellington, a banner calling for Italiano's ouster unveiled by fans pre-game.
Suffering their ninth defeat of the campaign, the Phoenix remain rooted in 11th place on the ALM table, with their hopes of playing finals on life support with eight games remaining on their season.
City had laboured in their attempts to find a breakthrough against the host's low block in the opening half, their best chance coming in the 14th minute when Aziz Behich picked out Tilio for an open header he would send wide.
But the visitors came out with guns blazing in the second stanza and were rewarded with a decisive breakthrough soon after.
