United also showed great resolve as despite a horror start to their campaign, sitting bottom after losing their first four games, coach Jim Booth and his side finished as the league's in-form side - losing just once in their last 16 games.
"It's huge. This is definitely the most important game of each player's life," he said.
"This is what we have been aiming for all season, and we will throw everything at it.
"It is crucial to give ourselves an advantage because everything changes when we are at their ground.
"We know Lynn Avon will be incredibly physical and tough to break down. I expect them to be a good passing team and we are already aware that they have some quality in attack."
The Villagers have the extra boost of fielding the top goal scorer in the Premiership - striker Mitchell Miller who has already scored more than 50 goals for his club this season and the division's player of the season - midfielder Alan Ferguson.
Ngongotaha will be at full strength with the return of skipper Haua and Ferguson from recent injuries and striker Josh O'Sullivan who is available after a one-match suspension.
Haua said his side would not change theattacking mentality they had played with all season and insisted the team must be "lethal" in front of goal.
"We are not going out to be conservative and play it safe," he said.
"The team must be clinical because this will be a very tight game and any missed chances could really cost us.
"We go into this game on a brilliant high and we have to keep this going."
Ngongotaha also have the added determination to redeem themselves after just missing out on the chance for promotion playoffs last season - finishing one point off the title race.
"This is so important for everyone involved at the club and I really think we could be on to something special here," Haua said.
"It would be huge for Rotorua football if we could get up into the Northern Leagues and really put us on the map.
"We need all the support we can get on the weekend, so we want the community to come out and help get us the result we crave."
NL Division Two Playoff series
Leg 1:
Ngongotaha AFC v Lynn Avon United, Saturday, October 1, Kick-off 2pm, Stembridge Rd, Rotorua.
Leg 2:
Lynn Avon United v Ngongotaha AFC, October 8, Kick-off 2pm, Parrs Park, Glen Eden.