The Blitzboks only scored late in the first half of their match against Japan en route to a 26-0 win, and then drew with Chile 5-5 in their second Pool C clash.
This makes their final pool match Sunday morning (00h10 SA time) against England a do or die affair if they want to keep their hopes alive of winning a fifth title in the Sam Boyd Stadium.
Springbok Sevens captain Philip Snyman did not mince his words in his assessment of their performance.
"It was shocking and almost a disgrace," said Snyman after the Chile match.
"This performance, especially against Chile, who are not even a core team on the circuit, was not worth the Blitzboks jersey. We need to have a hard look at ourselves before we front up to England."
Snyman said the lack of finishing and the lack of execution of the basics were not acceptable: "We could not even win our own line-outs and had so many scoring opportunities, but took none.”
South Africa 26, Japan 0
It took the Blitzboks almost the entire first half to outfox the Japanese defence. Branco du Preez finished strongly off his right foot after six minutes of frustration, with Japan targeting the breakdown area with great success.
The second half delivered a more fluent effort from the team as the bench made an impact.
Impi Visser scored after a movement that started when he won the kick-off at the restart of the half.
Selvyn Davids also rounded off a good run by Siviwe Soyizwapi before Mfundo Ndhlovu scored his first try in Las Vegas to confirm their second half dominance.
Sako Makata became the latest Blitzboks debutant in the second half of the match when he took to the field.
South Africa 5, Chile 5
Against Chile, Du Preez scored in the third minute after some good interplay, but when Chile drew level with their own try four minutes from the end, they picked up some real momentum.
JC Pretorius managed to get over the line in the last play of the match, but the officials ruled that he lost the ball over the line.