The Scots were beaten 9-6 by the Pumas at Murrayfield as a promising November series came to a disappointing end.
But Lamont, who was named man-of-the-match thanks to a fine individual display last weekend, is confident that Scotland are now a better side than they were three weeks ago.
"Overall it is a good improvement and we have to build on the A team winning the Nations Cup over the summer," said Lamont, after the Scots recorded impressive victories over Fiji and Australia before slipping up at the final hurdle.
"I know people will think about the Argentinian game as one that got away but two out of three is better than we have done in the past. As they say: 'Rome wasn't built in a day.'
Scotland are only just beginning life under new coach Andy Robinson, with the former England boss taking charge for the first time against the Fijians on November 14.
And Lamont claims he has seen enough in Robinson's short time at the helm to suggest that there is a bright future ahead for Scottish rugby.
"Andy Robinson has come in as coach and having brought a new management team with him the set-up still needs time to grow," explained Lamont, who could return to Magners League action against a number of his international team-mates when the Scarlets host Edinburgh on Friday night.
"There is momentum. We blooded a few players with Alex Grove doing really well in the centre.
"There's a good balance based on a couple of young boys coming through, a core of the squad which has been the same for a number of years plus some older, experienced players. No pattern goes straight up and there always has got to be a waver."
Lamont may be optimistic about the state of Scottish rugby but he refuses to gloss over the disappointment of Saturday's frustrating loss.
Robinson's men entered the clash with Argentina on an almighty high following their first victory over the Wallabies in 27 years, but they failed to live up to heightened expectations against a Pumas side that had already lost to both Wales and England.
And Lamont himself admits that the final performance of 2009 wasn't good enough.
"It's very deflating - losing sucks," added Lamont, after Scotland let slip a 6-0 interval lead.
"It was one of these games where at half time things were going well. Then, for the first 10 minutes of the second half, we wavered and allowed Argentina to get their tails up.
"We started to play their game - we should never have let them within range. They are a tenacious bunch who play with great passion. That can lead to great frustration on our part but it has to be kept in perspective.
"Andy Robinson is very disappointed as is everybody in our squad. What is it they say? You get four chances a game? You have to take advantage of them. It was a game we should have won."
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