Parramatta produced the unbelievable in toppling the team deemed unbeatable, ending South Sydney's perfect start to the season in a thrilling 29-16 victory at Pirtek Stadium on Friday night.

Against his former club, Eels maestro Chris Sandow orchestrated one of the gutsiest victories the club has seen in recent years to pip the high-flying premiers, who hadn't lost a game since their round 26 loss to the Roosters last year.

After dismantling Manly in round one, the Eels continued their giant-killing form at what has become a fortress at Parramatta to end a two-game losing streak.

Without Tepai Moeroa, Semi Radradra, Junior Paulo and Beau Champion, few gave Brad Arthur's men a chance of topping the competition top dogs.

But in front of a crowd of 15,562, the Eels played a brand of football the Rabbitohs were unable to contain and struggled to penetrate.

Parramatta wingers Reece Robinson and John Folau both bagged a double for the Eels, but it was Sandow who was the main man against his old club.

South Sydney had their fair share of chances to equalise in the final 10 minutes when trailing 18-12, but Parramatta's resilience in defence was a sight rarely seen from men in blue and gold for many years.

Sandow then landed the match-winning field goal before rubbing salt into the wound when he picked up the scraps from his grubber to score a four-pointer of his own on the stroke of full-time.

In the lead-up to the clash Anthony Watmough revealed his sadness in having to line up against close friend Glenn Stewart for the first time. Watmough admitted it was more emotional lining up against Stewart than it was playing Manly in round one, but you wouldn't have known it judging by their early exchanges.

The pair came together in the first set, with Stewart giving his former teammate some facial treatment that contributed to him spilling the ball.

In the next set Stewart found himself on report for a crusher tackle that left Watmough struggling back to his feet. It was some silky hands that led to South Sydney's opening points, producing a sweeping backline play to gift Joel Reddy a try in the corner.

But the Eels hit straight back through Folau, who ran a good line to bust through a hole and stretch out to score his first NRL try in just his second appearance.

Both teams went end to end for the majority of the first half until a penalty against Adam Reynolds for dissent presented the Eels with a two-point lead heading into half-time courtesy of the boot of Chris Sandow.

That lead was shortlived after Will Hopoate made a meal of a spiralling Reynolds bomb, allowing Alex Johnston to pick up the loose ball and offload to Chris Grevsmuhl, who showed great strength to get through three defenders to score.

Just as it looked like South Sydney would head to the break with a 12-8 lead, Folau once again proved too difficult to contain from close range, carrying four defenders over the line for his second try of the night and a two point half-time lead for Parramatta.

The Eels didn't take long to extend their lead, timing a backline play to perfection to get Reece Robinson outside his opposite number to give the Eels an 18-12 lead over the competition favourites.

Parramatta had a mountain of possession to start the second half, but South Sydney withstood an attacking onslaught to posts points of their own at the other end through Alex Johnston, however Reynolds failed to convert.

Robinson replied with his second try of the night before Sandow stepped up to seal the deal for the Eels.