Victory would secure Scotland a place in the quarter-finals ahead of the Pumas with one match remaining, the October 1 clash with England in Auckland.
Scarlets back Lamont, though, is only interested in the 80 minutes of play at Wellington Regional Stadium on Sunday.
Lamont said: "For me and everybody in the Scotland squad tomorrow is a massive game.
"It is, for me, the biggest game of my career so far. It is that important to us to get a good result and come away with a win.
"I will take a 3-0 win tomorrow if that's what it takes.
"I would be happy with that all the way through to the final - I don't know if the boss (Scotland head coach Andy Robinson) would be quite so happy about it.
"A win's a win, regardless of what way it comes.
"That's what a World Cup's about. It doesn't matter if you play beautiful rugby but lose, it's still a loss.
"I'd rather play ugly rugby and win."
Scotland were eliminated from the 2007 World Cup by Argentina.
Twelve of the 22 players involved in the quarter-final that day in Paris are in Scotland's 30-man squad in New Zealand, including Lamont.
The 30-year-old added: "Argentina are a quality side and they always step up massively for World Cups.
"The few games we've had with them over time have always been really close - a few of the results have been within one score of each other.
"It's always going to be a tough battle, but for the Scotland boys and myself it is the be-all and end-all tomorrow."
Lamont, along with Max Evans, is Scotland's most lethal finisher and Robinson has made a selection which he hopes will bring his wing duo into play.
Ruaridh Jackson has been selected at fly-half, with Dan Parks - the playmaker when Scotland won two Tests in Argentina in June 2010 - named on the replacements' bench.
While much has been made of Argentina's formidable pack - and Scotland will bid to counter that after selecting heavyweights Jim Hamilton and Richie Gray at second row, with tournament captain Alastair Kellock not even in the matchday 22 - Robinson also recognises the threat of their backs.
He said: "We've got full respect for the way that Argentina play.
"They've got a very good forward pack that understand how to give the side momentum.
"We know they can move the ball wide and they have a balanced game."
The Pumas' talisman and captain Felipe Contepomi has shrugged off a rib injury to play, but Robinson knows Scotland have to be wary of every member of the opposition.
The former England coach added: "Felipe's played against us in the centre before. We know that he's a very good operator.
"But it's not about one man. We can't focus just on Felipe Contepomi, we've got to focus on all 15 because they have a really good balance to the way they play.
"That's why it's always a really good Test match for us.
"They have strong forwards, so they're able to win the ball at the set-piece, and they have talented backs that have pace and are very good one-on-one runners."
Just two of the previous 12 Test meetings between the sides have been settled by a score in double figures, and Robinson knows it is imperative Scotland dominate the forward contest to prevail and called for patience from his side.
He added: "The side that keeps their discipline under pressure will be the side that wins this game.
"It will be vitally important that we are able to keep our discipline in this game."
The wind at the Wellington Regional Stadium, a port-side location renowned for swirling breezes, could have an impact on kicking at goal and out of hand.
Robinson added: "We're used to dealing with wind, we have wind all over Britain, particularly at Murrayfield at times and so we understand how it can change.
"What we've seen here is that it gets quite gusty, so it will change and it will change in specific parts of the pitch.
"We've got to be able to make decisions at key times depending on what's happening with the wind.
"It's the same for both sides - you just get on and you play with it. Our kickers have kicked well today so we're pleased with that."
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