Matsatsantsa moved into a two-goal lead inside the first 24 minutes thanks to goals from Denis Masina and Katlego Mashego, before Stars pulled one back nine minutes before the break.
But a flurry of three goals inside seven minutes for the hosts early in the second half from Masina, Daine Klate and Fikru Tefera saw Gavin Hunt's side decide the outcome of an action-packed match in their favour.
Defender Bongani Khumalo added a sixth deep into injury time to rub further salt in Ea Lla Koto's wounds.
Mashego almost gave United an early lead with a left-footed volley that hit the upright, but Masina was there to score just moments later with a right-footed shot.
Mashego doubled the hosts' advantage just past the midway point of the first half, scoring from close range, but Sthembiso Ngcobo pulled one back for Stars in the 36th minute with a low shot after being set up by Prince Olomu.
The score was 2-1 at the break but it took only 10 minutes of the second half for Supersport to regain their two-goal cushion.
Masina turned home Mashego's pass from 12 yards out to put Matsatsantsa well in control.
Just before the hour-mark Klate made it 4-1, shooting high into the back of the net after good work by Tefera, who himself got on the score-sheet in the 62nd minute after sweeping home a shot from Siboniso Gaxa's cross.
Khumalo made it 6-1 at the death, heading home Klate's cross to complete a wonderful performance by United.
Supersport leapfrog Ajax Cape Town and move into first place on 44 points, one ahead of the Urban Warriors. Stars remain in fifth place on 35 points and their outside chances of challenging for the title have all but vanished with this defeat.