Following a dispiriting defeat by New Zealand and an underwhelming win over Japan, Ireland were back to near their best against the Wallabies, with Mack Hansen scoring a first-half hat-trick before second-half tries from Caelan Doris, Ryan Baird and Robbie Henshaw.
But Farrell insists his players must find an even better performance to deny the Boks a first win in Dublin since 2012.
“I don’t think it will necessarily be enough, but I like the way that we got out of the way of ourselves,” added Farrell.
“Last week, after a couple of errors we just went within ourselves a little bit and it didn’t happen this week because there were plenty of mistakes.
“It’s always going to happen in Test match rugby anyway, never mind with the conditions the way they were. I suppose that’s the most pleasing part for me.”
Ireland have won four of the past five encounters with South Africa, but Rassie Erasmus’ side arrive in Dublin having beaten France and Italy despite first-half red cards in both games.
South Africa’s win over Six Nations champions France in Paris was especially eye-catching as they produced a stunning second-half performance to win 32-17 having trailed by a point at the break following lock Lood de Jager’s red card.
Asked what he likes most about the Boks from a coaching perspective, Farrell said: “I think it’s their energy and enthusiasm, which is probably driven from a couple of points of difference, one being the defence as in line speed, one being the breakdown and the other being the set piece.
“They get their energy from all of those bits because they do them really well.
“They know their own DNA but they’re able to add a few tricks as well with the type of personnel they have in their armoury.”
Farrell expects to have Garry Ringrose and Josh van der Flier available for selection again, but Stuart McCloskey may miss out after being forced off against Australia with a recurrence of a groin injury.
