Victory in their Pool B match at Wellington Regional Stadium would see the Scots qualify for the quarter-finals with only arch-rivals England to come next week at Eden Park.
The Pumas, who embarked on a remarkable run to third place at the last World Cup in France, would be all but eliminated given they have already lost to England.
Scotland beat Romania and Georgia in earlier matches.
"I'll take a 3-0 win tomorrow if that's what it takes. I will be happy with that all the way through to the final," Lamont told reporters in Wellington on Saturday.
"The boss (coach Andy Robinson) won't be quite so happy about it, but a win's a win regardless of what way it comes.
"That's what the World Cup's about. At the end of the day, you can play beautiful rugby and still lose. I'd rather play ugly rugby and win."
The teams are well acquainted, having met five times since the Argentines beat Scotland 19-13 in the quarter-finals of the last World Cup on their way to finishing third. Argentina have won eight of their 12 meetings overall while Scotland have won three of their last four encounters.
"Tomorrow is a massive game, the biggest game of my career so far. We obviously want to get a good result tomorrow," Lamont added. "A few of the results have been within one score to decide who wins so it's going to be a tough battle.
"For Scotland and for myself it's the be all and end all tomorrow."
While Argentina welcome back captain Felipe Contepomi, who suffered a rib injury against England and missed the Pumas' victory over Romania, coach Robinson said Scotland's focus was not on the talismanic 34-year-old.
"We know that he's a very good operator, but it's not about one man. We've got to deal with all 15 players," Robinson said.
"We have full respect for how Argentina play.
"We've played them on a number of occasions and we know they can move the ball wide and they have a balanced game.
"They obviously have a very good forward pack who understand how to get momentum.
"The Argentineans have got bright rugby players and they have understanding of how to get space for the backs."
The winner of the group will face the runner-up in Pool A, with Saturday's game between New Zealand and France set to determine the placings in that group.