Lamont has played in five RaboDirect PRO12 matches so far this season, helping the Scottish side's impressive charge up to third in the table.
But the Perth-born star, who also spent four years at Northampton Saints, was unable to bring the success of Glasgow's league season to the international scene as Scotland fell to defeat against Heyneke Meyer's side.
And having represented his country 70 times since his debut in 2004, Lamont was disappointed his team-mates didn't learn from their mistakes.
"I suppose as an old head I've been here many times," he said.
"There have been positive things but we're not winning. It doesn't matter what anybody says - if you don't win, nothing matters.
"We were up against the world number one and two challenging New Zealand and South Africa, but we could have been a damn sight closer in both of these games.
"When we beat South Africa two years ago I don't think we missed any tackles. We got low and brought them to ground.
"Despite being told by the coaches before this game and again at half-time to tackle low, to hit the breakdown harder, the fact we didn't do it is so frustrating.
"The reason the coaches tell us to do things is to win the game, and they were spot-on - it was a game that we could and should have won.
"They're not the most adventurous side and when you bring them down quickly they run out of ideas.
"Other than going through us a couple of times they didn't string any backs moves that got through, not like New Zealand."