It was Zambia's second win in four days over Algeria, who reached the last 16 at the 2014 World Cup in Brazil but have been eliminated from the race to play in Russia next year.
Zambia are in second place three points behind Nigeria and must beat the group leaders next month to have a realistic chance of reaching their first World Cup finals.
The 18-year-old Daka burst through after a fortunate ricochet off the home defence as they attempted to block Augustine Mulenga’s attempted pass in the 67th minute.
Algeria remained bottom on one point after four games as their fortunes continued to plummet.
Their African Footballer of the Year Riyad Mahrez had his first half penalty saved by Kennedy Mweene and his Leicester City team mate Islam Slimani missed a sitter with a back post header in the 77th moments after coming on as a substitute.
(Reporting by Mark Gleeson in Durban; Editing by Ken Ferris)
