South Sydney have drawn first blood in the battle of the NRL heavyweights, with a 34-26 win over bitter rivals Sydney Roosters in an absorbing encounter at ANZ Stadium.

The Rabbitohs grabbed the two points from a seesawing contest on Sunday, running in six tries to five in front of a crowd of 27,889 at ANZ Stadium.

The reigning premiers dominated the opening exchanges and raced into a 12-0 lead after 10 minutes, with efforts from Dylan Walker and Alex Johnston that were converted by Adam Reynolds.

But the game was turned on its head for the first time in the 19th minute when Reynolds left the field for a concussion test after his head crashed into the knee of Aidan Guerra.

During the halfback’s 11-minute absence, the Roosters scored three tries – two from Michael Jennings and a Daniel Tupou four-pointer – to seize the initiative.

The visitors extended their lead to 22-12 just after halftime when Dylan Napa scored his first NRL try and Trent Robinson’s men were well in control as their bitter rivals struggled to regain a foothold in the game.

But, out of nothing, Souths reduced the deficit when a penalty against Mitchell Pearce gave the Rabbitohs good field position and George Burgess powered over under the posts.

Burgess was denied a second try a minute later by the video referee only for Shaun Kenny-Dowall to put the Roosters back in control with a try in the right corner.

But that proved to be the last time the 2013 premiers troubled the scorers as the Rabbitohs fought back through Johnston’s second try before Joel Reddy’s 68th-minute effort restored their lead.

Issac Luke then added a late four-pointer under the posts in the final minute to ice the victory with Reynolds adding the extras.