Cape Town - Stalwart Werner Kok said he is frustrated by the Blitzboks' inconsistency, who added that the players must front up to their set standards.
South Africa were eliminated 29-10 by the USA in the Cup quarter-finals in Las Vegas, where Fiji, Australia and England also fell by the wayside at the same stage of the competition.
"This is a player problem, not a system problem," Kok said after play on the second day.
"We are the ones out there on the field and we need to fix this. The system works, but the people inside the system is letting it down.
"We need to work harder, our performances are not good enough. And it cannot continue like this," the former World Rugby Sevens Player of the Year added.
For Blitzbok assistant coach, Renfred Dazel, the lack of consistency is also root cause.
"The up and down performances of the day is the story of our season. We played such a wonderful technically correct and clinical match against England. And in the very next match against USA, we lose a scrum, we spill balls at the breakdown and we allow soft tries."
Dazel said they are expecting a tough match against Fiji: "They will be very physical and we need to combat that."
The Springbok Sevens team will face Fiji in Las Vegas on Sunday evening, not in the Cup competition of the Las Sevens as they had hoped, but rather in the semi-final for fifth place.
A call will be made on the fitness of Mfundo Ndhlovu on later on Sunday, before the third day kicks off, after he suffered an injury on the second day. If he is not available, Muller du Plessis will be called up, Dazel confirmed.
The match against Fiji will take place at 22:28 (SA time) on Sunday
The USA, New Zealand, Samoa and Argentina will contest the Cup semi-finals the fifth tournament of the World Rugby Sevens Series.