The defeat leaves Bafana Bafana at risk of missing out on next year's continental showpiece in Gabon and Equatorial Guinea.
"Our objective was to get maximum points and to not concede, and it all went horribly wrong," Tshabalala said in the Cape Times.
Bafana conceded two soft goals on either side of the break in Niamey, with Bernard Parker (poor marking) and Tsepo Masilela (missed clearance) at fault, before Andile Jali pulled one back with his first ever international effort.
Nevertheless, 'Shabba', who skippered the team in Steven Pienaar's injury-enforced absence, aims to stay positive.
"But there is still one game to go and all is not lost," he added.
Bafana must now beat Sierra Leone at home next month and hope Egypt, who fielded an experimental side in their loss to the Leone Stars, at least draw with visiting Niger in the final round of fixtures.