The man known throughout the oval ball scene as "Mighty Mouse" tipped skipper Mike Blair's side to bounce back from record defeat with a win over reigning world champions South Africa in Saturday's second EMC Autumn Test at Murrayfield.
McLauchlan is well placed to contrast the respective challenges of last weekend's 49-3 winners' New Zealand and what lies ahead.
As a player he shared in Lions Test series victories over the All Blacks (1971) and Springboks (1974) and says: "It'll be the difference between (facing) a rapier and a cutlass.
"New Zealand play with pace and cutting edge. South Africa will be much more physical.
"The challenge will be very, very robust and South Africa have won two games on this tour.
"They'll be up to speed and will learn from a lot of mistakes made against Wales. That will make them very formidable.
"Against that our boys are much, much better than Saturday's score reflected. They will be up to proving something."
The All Black defeat came in Scotland's first outing for five months.
McLauchlan added: "A lot of rust will have come out. I think there will be a huge step up in performance.
"I have every confidence in the boys. I think they will win it."
McLauchlan's prediction is partly based on what he regards as the best All Blacks team he has come across.
"New Zealand were just sensational. They had eight chances to score and took seven of them. They were the best All Blacks team I've seen.
"They said they were disappointed with the way they played against England saying they were very rusty and had worked hard on a cutting edge. But they were very physical as well.
"In some respects Scotland are very lucky to have a game like this one coming up against South Africa.
"If the All Blacks defeat had come at the end of the Autumn series our boys would have had three months to dwell on it which wouldn't have done anybody any good.
"Now they can get back out there straightaway and they can use that to their advantage in picking themselves up."
McLauchlan, who gained the second of his 43 Scotland caps in a 6-3 win over the Springboks at Murrayfield in 1969, picked out several players for special mention.
"Across the board the boys performed very well but it's just they were up against a very good side.
"Allan Jacobsen and Ross Ford did well and the back row stood up to them." For Jacobsen that will be regarded as special praise since he plays in the same No.?1 jersey occupied by prop forward predecessor McLauchlan, who added: "Young guys like Richie Gray stuck in and, as ever, you get what you get with the backs.
"The boys are disappointed that they were blown away. (But) they can use that."
"A lot of rust will have come out. I think there will be a huge step up in performance.