Australian captain Pat Cummins admitted that changes were possible after South Africa beat his side by 176 runs on the fifth day of the third test at Newlands on Saturday.
It was Australia's second successive defeat as South Africa clinched the series 2-1 and went past Australia to the top of the International Cricket Council's test rankings.
"I still think we're a really good side," Cummins told journalists. "Playing the now No 1 side in their own country, we had our moments in every test."
But he acknowledged that it was fair to ask whether there was a need for changes as Australia embark on a heavy programme of test matches over the next year.
"We'll be asking those questions internally as well," he said. "We need to get better if we want to get back to No 1. Maybe there will be some changes in style, changes in the personnel."
Cummins said any chance of Australia chasing down a target of 288 was destroyed when Kagiso Rabada took two wickets in the first over and followed up with a third in a devastating opening spell which ripped out Australia's top three batsmen.
They were bowled out for 111, with off-spinner Simon Harmer taking a career-best six-for-16 in 21.1 overs.
South African captain Temba Bavuma said the series win was a tribute to the character of his team.
Bavuma said the partnership between century-makers Ryan Rickleton and Wiaan Mulder on the fourth day had shown the resilience of the team after they had been behind the game after three days.
"When the batters did what they did, the bowlers had the confidence. The way Rabada started today he got everything going. From then on we were able to keep a tight grip on things."
Bavuma said Harmer's man of the match performance –- he had match figures of 10 for 120 –- illustrated the strength of South Africa's bowling attack.
"It's been the backbone of our team," said Bavuma. "It's been a big part of why we've been successful. When the wicket suits the fast bowlers, we have the guys. And when the spinners come into the game, we also have that ability."