Paraguay's 3-1 win over Slovenia ensured they progressed to the last 16 from Group B by virtue of having scored more goals.
Sono said: "It's unfortunate that Paraguay beat Slovenia but that's the name of the game.
"We did well, we showed guts, but we gave away three silly goals and got punished.
"We can't blame anybody. We're going home. We played well but it happens."
"We played some good football, we gave it our best shot, but this sort of thing happens.
South Africa's first round exit casts doubt over sono's future but he said: "I'll decide when I get home."