Bafana Bafana beat their hosts 3-1 at a packed Somhlolo National Stadium thanks to second-half goals from Thulani Hlatshwayo, Thabo Mnyamane and Mandla Masango.
However, Mashaba was utterly disappointed at the solitary goal conceded after his defence failed to clear their lines from a Swazi corner, when Felix Badenhorst shrugged off a challenge from Thapelo Morena to send the ball flying past Jackson Mabokgwane.
“The goal [Swaziland] scored, my defence have got to be punished for that,” Mashaba said after the match.
“It was more of a soft goal as well, we should have defended that ball.”
Despite the defensive error, ’Shakes’ felt his boys impressed given that they only trained together for two days.
“But the boys' performance as well; they did very well,” he added.
“Unfortunately with the national teams, you get players for two days and the third day you’re playing.
“You don’t have time to solve the problems and, until that has been sorted out, I think we will see better football in the national team.”
Bafana next host Nigeria at Mbombela Stadium on Sunday, in what is labelled as a 'grudge match' for the Super Eagles, who were knocked out of the Afcon qualifiers by Mashaba’s men.
The west Africans lost 1-0 at home to Uganda in their respective midweek friendly.