"I've never been more disappointed - not only in my own performance in the second innings, but the result... I'm hoping that's as poor as it gets in my career," Clarke said on Friday after the match.
"If you don't feel the pain here, you'll never feel the pain and you're playing the wrong sport, for the wrong team but, there’s also the other side that in this great game you need to find a way to get back up.
"Good teams do and that’s how they learn."
Australia started their second innings with a 235-run advantage but were sent packing for just 47 runs, their lowest Test total in over a hundred years.
"If there's one person in that change room with a smile on their face... every single one of us needs to be disappointed, for good reason."
The pendulum had swung Australia’s way until lunchtime on day two, after Clarke himself had completed a magnificent 151-run innings.
The tourists went on to bowl out South Africa cheaply and had thought they were in the pound seats.
Shane Watson (5/17) had bowled superbly, taking the second fastest fifer on record in just 19 balls, and South Africa were dismissed for 96 runs before tea.
But disaster was to follow and their efforts were overshadowed when they found themselves at 21/9 -- a record in itself -- for a top order.
"The performance with the bat (in the second innings), I've never experienced - not that bad, not 9 for 21.
"The lowest Test score ever is 26, so we needed our number 10 and 11 to save our backsides there - that's unacceptable."
Clarke said nothing could detract from their shocking batting performances but it was compounded by poor bowling and fielding during the Proteas’ second innings on day three.
"I don’t want to hide away from how bad we played in our second innings, but I also don’t want to hide away from the fact that even if we had made 600 in our second innings, the way we came out and bowled on Friday and South Africa batted, there still would have been a chance of losing.
"We just weren’t good enough with the ball and, just like nobody means to get out, nobody means to drop catches, but there were a couple of costly catches as well."
Clarke said while they had bowled well in periods, it was not good enough against such tough opposition and on a wicket that still had something in it.
"They didn’t shave any grass off the wicket overnight so there was still going to be seam there, but we had to hit our areas more consistently and we had to hang on to every single chance we got."
On team changes, Clarke said it was still too early to decide as they were still needed to process their heavy defeat.
"I’ve got to get through today(Friday) first. We’ve only just come off the field so I’ve got to sit and have a look at exactly what’s happened and communicate with the guys in the team firstly, that’s my priority.
"I don’t know the answer to that question at the moment. I think I need some time."
Clarke's challenge is to ensure his team’s crushing defeat does not leave them psychologically damaged ahead of next Thursday's second Test in Johannesburg.
"I’ve learnt more from the not-so-good days than the good days," he said.
"That’s what I’m hoping everyone in that change room does - finds something so when we get into a position like we did in that second innings with the bat, or on Friday with the ball, we go about it in a different way.
"We've obviously got a lot of work to do in all facets of the game to get ourselves as right as we can for this second Test.
"We still have a chance to level the series. That will definitely be our goal before we get on the plane back to Australia."