Scott Wara received a yellow card in the opening minute, putting Bula FC under early pressure.
South Melbourne FC capitalised, with Yuki Uchida scoring in the 20th minute before Max Mikkola extended the lead in the 30th minute.
South Melbourne FC were leading by 2-0 at halftime.
In the second half, Kaile Auvray was shown a yellow card in the 56th minute, while Nabeel Begg was also booked late in the 89th minute.
Auckland FC leads the standings with 29 points.
Meanwhile, South Melbourne FC remains second on the points table with 22 points, while Bula FC sits in third place with 18 points.
Bula FC will now face table leaders Auckland FC this Saturday at 7pm at 4R Stadium, Govind Park in Ba.
