A similar plan paid off for the Reds when they undid the Durban-based outfit by basing the majority of their attacking raids on the Sharks wingers.
But Plumtree believed his team had rectified that weakness, which he says was evident in its win over the Force last weekend.
Plumtree expected Brumbies coach Andy Friend to prepare similarly for Saturday morning's encounter.
"Defensively we were poor against the Reds, we didn't get off the line and when they went wide we weren't ready for it and struggled to stop them," Plumtree said.
"One team has been successful in bringing us down that way but other teams won't, because we've fixed the issue.
"We did a lot of work on it in the lead-up to the Force game and came out and gave them nothing in defence."
Friend revealed he would target the Sharks out wide when the teams clash early Sunday morning.
The Brumbies will also employ a rushed defence, which was the primary ingredient behind the team's first win in Durban two years ago under former coach Laurie Fisher.
"You've got to be direct at them," Friend said.
"They're a very physical side and while that would err most teams from rushing up in defence against them, I think it's a sign that you've got to take it to them, to beat them at their own game.
"They've also got a passive defence out wide which we'll try to exploit but to be able to do that you've got to dent them first, go through them, and then go wide."
The Sharks returned to South Africa late on Sunday night following a four-match road trip to Australia and New Zealand, which netted three wins.
The Brumbies lost to the Lions last weekend in what was their first match on tour after their 13-hour flight from Australia.
Plumtree believed the fact his side flew from Perth not from Australia's east coast would give it an advantage in terms of recovering from jetlag.
"The boys had on Monday off to get over the flight, we had a light run Tuesday then had on Wednesday off as well so while it definitely is a long flight, I think the fact we only had to come from the west coast combined with a light week of training should make us OK," he said.
"The travel does take a lot out of you, maybe as the Brumbies found out last week, but our boy are fresh.
"Also the fact we're in front of what will be a pretty loud and parochial home crowd should help the lads too."
The Brumbies trained on Thursday morning and will have their captain's run at Absa Stadium on Friday.