Forward Jim Hamilton admits Scotland need to find a cutting edge in order to beat the leading nations.
The Scots produced a battling display in their 21-15 defeat to Australia at Murrayfield on Saturday but were unable to score a try as Greig Laidlaw kicked all of their points.
Montpellier lock Hamilton, who was winning his 50th cap for the Dark Blues, said: "If we are taking the positives out of it, we were significantly better than we were last week against South Africa.
"But we still struggled at those crucial times when we needed to be clinical. The chances we got, we didn't take.
"If you look at these huge southern hemisphere nations, if they get one opportunity, they make it count by scoring.
"We are obviously not quite at that level but we can be pleased with the fight and resolve that we showed in some parts against Australia.
"We were in a good place going into half-time but the disappointing thing was that we allowed them to get a second try just after the restart.
"But if we want to move on as a team, we can't just talk about positives. We have to be harsh in our assessment of ourselves.
"We need to be brutally honest with each other but we have got the coaches who will do that.
"It's not about blowing smoke into the team and telling us all how great we are. Frankly, if you don't win then it really doesn't matter how well you have played."