Valdes had come on as a substitute for skipper Iker Casillas at half-time, but needed to leave the field with 13 minutes to play.
Spain had exhausted their substitutes already, and sniffing a memorable victory, Bafana Bafana boss Gordon Igesund needed some arm twisting to allow Pepe Reina to replace Valdes.
Initially defender Alvaro Arbeloa had donned the gloves, but sanity and friendliness prevailed, and Reina was allowed to complete the match between the sticks.
All the while, Valdes was receiving treatment off the field, with Barca likely sweating on a report regarding the extent of their number 1’s injury.
After the match a statement from the Spanish Football Federation read: "Victor Valdes, possible calf tear of the right leg.
“This Wednesday he will have new tests at his club to determine the exact extent of the injury. The national team doctors treated the goalkeeper immediately after he retired from the game in the 77th minute.
"They have determined that he could have suffered a torn calf in the right leg. Valdes was injured after going to clear the ball in a dangerous South Africa counter-attack."
If he has indeed torn a muscle, Valdes faces some time on the treatment table.
There he will join Lionel Messi, who will not play again this year.
And with Barca short of options at the back as well, the spine of their so far unbeaten team has suddenly begun to bend under the pressure the football season can present.