The Welsh forwards, despite the loss, had the ascendancy against Australia last weekend and marched forward at scrum-time
And du Plessis has admitted the Springboks were impressed by the dominant display.
The front row trio of Gethin Jenkins, Matthew Rees and Adam Jones have a track record of causing the South Africans problems.
The most notable of those came on the British & Irish Lions tour of South Africa last year, where an all-Welsh front row rescued a back-pedalling scrum in the first Test.
The troublesome trio were rewarded with starting spots in the second Test and dominated the scrum until Jenkins and Jones picked up injuries.
“They are a unit that Wales relies on,” said du Plessis.
“They were tight and together. They have a settled combination and have played a lot of Tests together.
“They are quality individuals and it is going to be a tough test for us. They’re a formidable unit and they scrum well together.
“It is difficult to rate them but they can match any front-row in the world. Wales scrummaged Australian to pieces so I think they can be very happy with their performance.
“Australia have scrummaged well this season. I have played against the Aussies a few times and we could never do that to the Wallabies.
“So hats off to the Welsh and they got good reward for scrummaging well. They got a few penalties and the Wallabies knew they were under pressure.”
Du Plessis will pack down opposite Gethin Jenkins and singled the Cardiff Blues powerhouse out for special mention.
“Gethin Jenkins is the complete player,” continued du Plessis.
“He can tackle and run with the ball and force turnovers. He is a big leader for Wales and he will be an asset to any team.”
Du Plessis put Wales’ loss to the Wallabies down to basic errors and maintains they still have the players to hurt any team.
“Wales were a bit unlucky against Australia and they will be disappointed.
“They gave away some silly tries which were against the run of play. They are always a tough team to play against.
“If you look at all three games it was key moments where one guy made the right key decisions.
“Sometimes it is the lack of concentration and teams are more switched on.
“But Wales have the players to do what Australia did and you just have to see how they came back from 20 points against Scotland earlier this year.”
