A first-half try by captain Siviwe Soyizwapi was added to after the interval by Chris Dry and replacement Seabelo Senatla. None were converted.
"We call ourselves a defence team, and we're proud of it,” Soyizwapi said.
Having won Dubai for a record seventh time, and fourth time in the last six tournaments, South Africa goes to its home Cape Town Sevens next weekend leading a world sevens series it last won in 2018.
“The rust is off and we're keen to play at home,” Soyizwapi said.