Mapusua was part of the side that lost to England at Twickenham
Seilala Mapusua says his Samoa side must match Scotland's never-say-die attitude if they are to avoid a third straight defeat in the British Isles.
Samoa lost 26-13 to England on the same day as Scotland were defeating world champions South Africa in Edinburgh.
"Watching Scotland against South Africa, they really got stuck in," said London Irish centre Mapusua.
"And I think, in the end, it was the defence that won them the game. We know how strong their forward pack is."
The Scots, who suffered a hammering by New Zealand in their opening autumn Test at Murrayfield, bounced back with a victory that lifts them to an all-time high of sixth in the world rankings.
"They had a never-say-die attitude and I think we're going to be in for quite a physical encounter on Saturday," Mapusua told BBC Scotland, picking out the pack as Scotland's main strength.
This team has really shown that it has come a long way
Samoa centre Seilala Mapusua
"We're going to have to match it otherwise we will be going backwards all day.
"Whilst we don't mind defending, we can't defend for 80 minutes and expect to come away with a win.
"So we will be working hard on the set-pieces this week."
Mapusua, whose side lost their opening Test match 20-10 to Ireland, thought they came away from Twickenham with their heads held high.
"We asked the boys at the beginning of the game to give a performance they could be proud of and I think there wasn't one Samoan who wasn't proud of their performance," he said.
"To defend the way we defended and for the length of time - I think we might have had 30% possession - shows the character of this team and how much it has progressed."
Mapusua thought that, in previous seasons, Samoa might have capitulated in the second half, despite having gone in at half-time only 6-3 down.
"This team has really shown that it has come a long way," he said.
"I think our forwards were immense in defence, but they really want to work on the set-piece and also ball retention.
"We didn't have a lot of ball and we need to make better use of what ball we do get."
Mapusua thought that the success of the Samoans on the world sevens circuit was paying dividends, with several players progressing to the full national squad.
"They bring in a bit of extra pace and flair - and also a winning mentality," he added. "They expect to win and that can only enhance the squad.
"They are big, they are fast and they can tackle - and that's what you want from your loose forwards."