The Springboks are out to snap Wales’ run of eight wins in a row when the two teams meet in Cardiff on Saturday.
Included in that run is the Dragons’ 22-20 win over the Boks in coach Rassie Erasmus’ first Test in charge in Washington earlier this year.
Since the start of the month, coach Warren Gatland’s team have gotten the better of Scotland, Australia and Tonga.
And Erasmus knows it will be a tough challenge.
He says: “The way they’ve been playing, they’ve beaten proper teams and they’ve got experienced players.
“It’s a tough match; we have four tough matches on the tour and although we lost the one against England, we’re ending off with the toughest one of the four.”
Of his opposite number on Saturday, Gatland, Erasmus adds: “He went to New Zealand and won the series there with the Lions - that says a lot about the man.
“The way he is building depth for the World Cup; he’s learnt from his previous lessons.
“He is building quality depth, which is a warning to the rest of us.
“Playing them at home; they’re on a great run [will be a big challenge].”