National's Hekia Parata is a strong challenger and there are no right-wing candidates threatening to significantly erode her vote, while Mr Faafoi's support is going to be split by unionist Matt McCarten and the Green's Jan Logie.
Mr McCarten has run a hard campaign, targeting people in the mainly low and middle-income electorate on the outskirts of Wellington with calls for the minimum wage to be lifted to $15 an hour and a sharp focus on unemployment, the cost of living and the housing shortage.
"He's made the job harder for us but we stepped up the effort and we're confident we're going to get there," Mr Faafoi said yesterday.
"We don't think he's going to make that much of an impact that he would dent our chances of winning."
But although Mana will almost certainly still be a Labour seat on Sunday morning, Mr Faafoi isn't likely to hold a majority as strong as the 6155 gained by Winnie Laban in 2008.
Ms Laban, who caused the by-election by resigning her seat to take up a position at Victoria University, had held Mana since 2002 and generated a strong loyalty vote.
Mr Faafoi is a new boy on the block and doesn't live there, although he is committed to moving in and has strong family ties in Mana.
Labour is also mindful that although Ms Laban held that big majority, the party vote in 2008 was much closer and Labour's majority was 2508.
That indicated the strength of Ms Laban's personal popularity, and Mr Faafoi is starting from scratch.
Ms Parata, a current list MP, ran against Ms Laban in the last election and Mana is familiar territory.
"We've been very organised and on top of the issues that are important to these communities," she said.
"By Saturday we will have done all that it's been possible to do."
She has had strong support from Prime Minister John Key, who has smiled his way through the streets and shopping malls of Porirua.
"Win, lose or draw, she's run a fantastic campaign and proved herself to be a hard-working, articulate and intelligent candidate and Member of Parliament," Mr Key said.
Labour's biggest worry is a low turnout, and every voter Mr Faafoi has been able to shake hands with has been given the message -- get to the booths on Saturday.
Mr Key knew the score on that: "If our voters turn out and their voters don't, you've got a new MP."
