The Rabbitohs 16-6 at the half time break and 26-6 with 20 minutes left on the clock, but a spirited comeback from the Tigers almost led to another narrow defeat for the South Sydney under 20s.
Prop Daniel Smith was held up over the line in the ninth minute, but it would only take three more minutes for co-captain Cameron McInnes to score the Rabbitohs' first try. Will Paterson converted to take the score to six-nil.
Four minutes later halfback Christian Hazard scored his first try, and Paterson's conversion extended the lead to 12 points.
The Tigers hit back through Luke Williams in the 30th minute and Manaia Rudolph's conversion reduced the deficit to six.
A try to Aaron Gray in the final minute of the half gave the Rabbitohs a 16-6 lead at the break.
Hazard scored his second in the 46th minute after a long break from Gray, Paterson's conversion taking the scoreline to 22-6.
Gray then added his second try in the 59th minute of play, extending the lead to 20 points.
The Tigers mounted a huge comeback through tries to Shane Lalogafau (64th minute), Dallas Graham (67th minute) and Manaia Cherrington (72nd minute), reducing the deficit to two points.
Strong defence in the closing minutes would hold see the Rabbitosh hold out the Tigers, scoring a well-deserved 26 points to 24 win.
South Sydney Rabbitohs 26 (Christian Hazard 2, Aaron Gray 2, Cameron McInnes tries; Will Paterson 3 goals)
Wests Tigers 24 (Luke Williams, Shane Lalogafau, Dallas Graham, Manaia Cherrington tries; Manaia Rudolph 4 goals)