Durban - It will go down as the most calamitous collapse in Proteas Test history, and while Sri Lankan hero Kusal Perera deserves all of the credit after one of the game's great knocks, South Africa will take a while to get over this one.
As stunned skipper Faf du Plessis said in the immediate aftermath of the game, the reasons for what went wrong in that final hour and a half will take a day or two to sink in.
The undefeated 78-run stand between Perera and Vishwa Fernando is the highest 10th-wicket partnership to have ever been recorded in a successful Test match run chase.
Nothing the Proteas did worked.
Even when Sri Lanka were still 80 runs out, Du Plessis employed an ultra-defensive field against Perera. At some stages, there were eight South Africans on the fence to Sri Lanka's new main man.
The plan, of course, was to restrict Perera's scoring as much as possible while the Proteas wanted to bowl as many balls to the tail as possible.
Perera, though, felt no pressure with the field back and he worked his twos, hit his boundaries and took the singles at the most inconvenient times for the hosts.
South Africa simply didn't bowl enough balls at the tail, and while that may have been down to some questionable tactics, it was mostly down to Perera's brilliance.
Even when the Proteas did get their chance to bowl at Fernando, who was clearly uncomfortable, they could not get the job done.
Dale Steyn was too short, Kagiso Rabada could not hit the stumps with his yorkers and it all unravelled for Du Plessis and his men.
Perera hit 5 sixes in his knock, but the two he hit off back-to-back Steyn overs were the most memorable.
Steyn, one of the great fast bowlers of all time, was dispatched over square leg and deep into the stands with a brand-new Kookaburra in his hands.
By then, Du Plessis and the Proteas knew that they were on the verge of a loss that would raise serious questions.
This is a World Cup year and watching Steyn and the Proteas wilt under pressure will ring the alarm bells.
South Africa's inability to rise to the occasion when the heat is turned up is well-documented in World Cups, and while this is obviously a different format entirely, the likes of Steyn, Rabada and Du Plessis will be key figures in South Africa's charge in England later in the year.
And, when the pressure was at its highest on Saturday, South Africa's old demons started rearing their heads once more.
Nobody at the post-match press conference on Saturday used the word 'choke', but it did not take long before Du Plessis was asked about the World Cup concerns that arise from losing a match from such a dominant winning position.
"I don't see that. The pressure of Test cricket is very different," the skipper said.
"You're bowling to one player the whole time and some days you just have to say, 'well played'.
"It wasn't through our mistakes where we dropped catches and things like that. It was purely a super-human effort with the bat and when that happens in Test, T20 or ODI cricket then that's got nothing to do with us and pressure. It's got to do with how someone else plays.
"There have been no chats about World Cups since the Test team got together."
Undefeated in a home Test series since taking the captaincy in 2016, Du Plessis was clearly distraught at the result.
Not only was Saturday the lowest point of his time as skipper, but the result means that South Africa cannot win this Test series with only next week's Port Elizabeth affair to come.
With Du Plessis desperate to take the Proteas back to No 1 in the world, failure to beat Sri Lanka on home soil will do nothing for the Proteas in that endeavour.
The second and final Test gets underway on Thursday.