Rabbitohs 28 Knights 10
The Rabbitohs shrugged off the quick turnaround from Monday night's win over the Bulldogs to continue marching up the NRL ladder.
The result left Newcastle lamenting another loss, compounding the difficulty of their early season drug scandal and making their sole win in the opening match against the Bulldogs look a distant memory.
The key period came in the middle 20 minutes of the second half. Souths warded off a sustained period of attack from the Knights, which saw them concede one try to a clever overlap created for wing Akuila Uate.
The Rabbitohs then struck back with two tries to wings Futeli Talanoa and Nathan Merritt (his second) to make the score 22-10 and put the result almost beyond doubt.
A chief Rabbitoh protagonist throughout was Isaac Luke in the hooker role, doing his Kiwis' chances no harm. He darted back and forth around the ruck, continuing Souths' penchant for dummy-half line breaks.
But not even he could match second-rower Dave Taylor's finesse threading the crucial grubber that helped turn the Newcastle defence around and allowed Talanoa to win his foot race in the 63rd minute.
The Knights made the most of the play early in the first half, but still couldn't match the Rabbitohs on the scoreboard.
The visitors' defence held firm for the most part, tackling tenaciously against Newcastle's 54 per cent possession, slipping only to let prop Daniel Tolar through on a bustling run.
Centre Junior Sau also proved problematic, demonstrating his fleetnees of foot. He will also be in the frame for ANZAC test selection in a black jersey.
That helped the hosts clock up 18 tackle breaks to 11 in the first 40 minutes but their completion rate let them down in the latter part of the first spell.
In contrast, South Sydney seized their opportunities. Luke crabbed across field from dummy-half to find space for Nathan Merritt on the right flank and, as he did on Monday against the Bulldogs, centre Beau Chapman seized on the counterattack from a misfired kick in the 33rd to bolt a straight 60 metres for the tryline.
The Knights were lucky not to be three tries down at halftime when Sam Burgess spilt the ball three metres short in the 31st minute.
South Sydney 28 (N.Merritt 2, B. Champion, F. Talanoa, R. Wesser tries, I.Luke 4 goals) Newcastle 10 (D.Tolar, A. Uate tries, W Naiqama goal); Halftime: South Sydney 12-4.