Souths forward Ben Te'o was put on report for a lifting tackle on Jarrod Croker in the 57th minute.
The Rabbitohs' attack had no trouble finding holes in their absence, however, with halfback Adam Reynolds scoring two of his side's seven tries and adding one assist, while young playmaker Luke Keary held his own in front of the 9,526-strong crowd.
Wingers Alex Johnston and Bryson Goodwin also got in on the action with two tries apiece.
The win lifts the Rabbitohs to second on the ladder, two wins behind front-runners Manly.
Josh Papalii (142 run metres) was the standout for the Raiders, while prop David Shillington (127m) continued his strong form.
Barring two late tries, the majority of the Raiders' performance was abysmal, their completion rate hovering around 64 per cent and gifting Souths the lion's share of possession and territory.
They did start strongly, capitalising on some ill-discipline from the Rabbitohs and taking an early lead courtesy of a penalty goal.
It took the Rabbitohs just a set-and-a-half to hit back, however, with Dylan Walker exposing the Raiders' flimsy left-hand fringe defence in the sixth minute.
Another four minutes later, Souths crossed again through the Raiders' left edge, a superb cross-field kick from Reynolds finding a flying Johnston to go up 8-2.
A Goodwin try in the 27th minute put the Rabbitohs up 12-2, the three missed conversions from Reynolds making the half-time score a lot closer than it should have been.
Johnston picked up his second shortly after the break when Raiders fullback Anthony Milford left a grubber to go dead, only for the ball to bounce on its point and be grounded millimetres before the dead-ball line.
Raiders winger Sami Sauiluma then pulled off some spectacular acrobatics of his own to score next to the corner post to keep his side in the hunt at 16-6.
However Reynolds' 62nd minute converted try, and then Goodwin's second try from a bomb three minutes later, put any hopes of a comeback to bed.
Reynolds then picked up his second in the 70th, before Croker and Milford crossed for two late consolation tries for the Raiders.
- AAP