The Giants started the match positively when Imran Tahir caught Theunis de Bruyn for six off the bowling of Chris Morris in the third over.
Problems continued for the Spartans three balls later, when Morris registered his second wicket of the night by trapping Proteas Test opener Dean Elgar in front without scoring.
The Giants were on a high when they captured their third wicket in the fourth over, Vaughn van Jaarsveld returning to the pavilion for just one after being run out by Junior Dala.
The fourth wicket arrived in the sixth over, when Spartans captain Heinrich Klaasen was caught by Morris at square leg off the bowling of Dala.