Dugan, who missed the first four rounds last season after injuring the same knee in the corresponding match, suffered the injury trying to avoid an oncoming teammate as he fielded a South Sydney grubber in the 46th minute.

The NSW Origin representative immediately clutched at his knee as he fell to the turf in agony, but managed to play on after receiving some attention from the club's trainer.

However his night came to an end a few minutes later, taken up the tunnel for further examinations on the injury he suffered in what was his return to fullback after finishing last season in the centres.

Coach Paul McGregor said Dugan would undergo scans on Monday but the fullback was upbeat about his chances of leaving with his teammates for England in a week's time for the World Club Series.

"I think he's okay. He wanted to play on there so that's a really positive sign," McGregor said.

"If a player wants to stay out there, it can't be too serious but you never know until you get that scan.

"It didn't look good from the screen but he tells me he's okay. But he's hyperextended (his knee) pretty bad so we'll see."

The Rabbitohs returned to ANZ Stadium for the first time since their drought-breaking premiership triumph four months ago, and despite retaining the Charity Shield after winning the match last year, they looked a vastly different football team both on paper and with the ball in their hands.

With the NRL premiership and Auckland Nines trophies securely locked away in their trophy cabinet, the Bunnies added another piece of silverware to the cupboard before they head over to England for the opportunity to be crowned world club champions.

With Greg Inglis, Adam Reynolds, George Burgess, John Sutton and Glenn Stewart watching from the sidelines, the usually meticulous Rabbitohs were anything but in their first match of 2015, coming up with some uncharacteristic errors in an uninspiring preseason hit-out.

Coach Michael Maguire insists all the players who missed the Charity Shield will be available for the World Club Challenge.

"A lot of the boys really wanted to play," Maguire said.

"George, he pulled out last night along with Reyno and Glenn Stewart. The three of them really wanted to play because it was a chance to get a good hitout."

The Dragons showed some signs of promise despite an apparent lack of grunt up front, and while their attack looked disjointed at times, their defence held firm for three quarters of the match in front of a crowd of 16,821 at ANZ Stadium.

It was a vastly improved performance to the one they dished out in the Charity Shield at WIN Stadium last year, where they showed few signs of encouragement in the 38-20 loss on home soil under former coach Steve Price.

The biggest concern surrounding the Dragons this season will be whether they get into enough try-scoring positions to win matches given the shortage of muscle in the middle.

But thanks largely to South's inability to control the ball, those opportunities were aplenty on Saturday night despite only yielding just 12 points.

The Roosters were unable to go back-to-back last year with almost the identical team that won the grand final in 2013, falling short in the preliminary final.

For South Sydney, their title defence will prove an even tougher assignment considering one of their most influential players, Sam Burgess, is playing rugby union in England.

The Rabbitohs have also lost Ben Te'o (rugby union) and centre Kirisome Auva'a (suspension), but have welcomed former Origin players Stewart and Tim Grant to the fold.

It took 24 minutes but the Dragons finally capitalised on a mountain of early possession to post first points of the match after Benji Marshall danced around Luke Keary from an attacking scrum to give his side a 6-0 advantage.

The second try didn't come until the 53rd minute when former Panthers winger Eto Nabuli showed great awareness to catch a cross-field kick and pass it back to Charly Runciman to score despite being centimetres from stepping on the sideline.

South Sydney managed to get on the scoreboard in an unorthodox manner after Sam Manulelua picked up a dropped ball from the Dragons to sprint 70 metres untouched, before Chris Grevsmuhl barged over from close range to equalise with four minutes remaining.

The Rabbitohs head to England for the world club challenge against St Helens next Monday, while the Dragons depart the next day for their match of the World Club Series against Warrington the same weekend.