The Rabbitohs led 12-6 at half time and went on with it in heavy conditions in the postponed home game.
South Sydney opened the scoring in the tenth minute when winger Tyrone Phillips dived over in the left hand corner following a well-constructed movement by the backline after moving 90 metres up-field in the set. Cameron McInnes converted to establish a six-nil lead.
The Rabbitohs kept the Raiders under pressure in the wet conditions thanks to the terrific kicking game of young halfback Christian Hazard.
The pressure led to points in the 28th minute when fullback Alex Johnston, backing up from the NSW under 18s' victory over QLD on Wednesday night, made the most of a McInnes break to score under the posts. McInnes converted from in front to take the lead out to 12 points.
Winger Siosaia Tanginoa was put on report for a shoulder charge which looked to be a little extreme, but the Rabbitohs were muscling up in defence with Duncan Low, Aaron Gray, McInnes and Daniel Smith busy in the defensive line.
The Raiders scored their only try of the first half in the 35th minute through five-eighth Jordan Worboys, and Mitch Cornish's conversion saw the Rabbitohs head to half time with a 12-6 lead.
It only took three minutes of the second half to see Phillips cross for his second try, again seeing a well-worked play pay dividends for the left winger.
The Raiders struck back three minutes later with Worboys scoring his second try, and Cornish's conversion reduced South Sydney's lead to four points.
Both sides were hitting hard in defence which saw some turnover of the ball, but the Rabbitohs regrouped the better to see Tanginoa force his way over the line from short range in the 56th minute. McInnes converted to take the lead out to ten points.
The Rabbitohs then had to continue to muscle up in defence with back rower Nick Hedley and front rower Brad Croad working particularly hard.
The Raiders blew an attacking opportunity with ten minutes on the clock, and some wonderful commitment in defence was shown by Rabbitohs five-eighth Jake Watts in the 77th minute, saving a try despite struggling with a chest injury.
The Rabbitohs were able to hold the Raiders out and recorded a solid 22-12 win in the wet over the competition leaders.
The Rabbitohs will now prepare to take on the New Zealand Warriors next Saturday at 1pm at the Suttons South Sydney High Performance Centre at Redfern Oval.
South Sydney Rabbitohs 22 (Tyrone Phillips 2, Alex Johnston, Siosaia Tanginoa tries; Cameron McInnes 3 goals)
Canberra Raiders 12 (Jordan Worboys 2 tries; Mitch Cornish 2 goals)