A magnificent defensive performance has helped propel Cronulla into the top four for the first time since 2008 as they overcame St George Illawarra 12-0 in Saturday’s NRL clash at Toyota Stadium.

In a high-class encounter, the Sharks spent large periods of the game on the back foot, but showed great determination to hold out their local rivals for their fourth successive win and delight the 21,380 fans – their biggest crowd since 2004.

Todd Carney also gave his hopes of a NSW call-up a boost by outshining incumbent five-eighth Jamie Soward as the Sharks held the Dragons scoreless for the first time since 1973.

The Sharks opened the scoring in the seventh minute through veteran hooker John Morris, who finished off a superb five-man move that sliced through the Dragons’ defence.

It proved to be the only score of the opening period with both sides playing their part in an absorbing encounter, Sharks skipper Paul Gallen leading the way with another tireless performance as he clocked up 223 running metres and made 39 tackles.

In the second period, the Dragons came racing out of the blocks but the Sharks withstood wave after wave of attack, with wingers Matthew Wright and John Williams defusing a number of bombs from Soward to frustrate the visitors.

The longer the Sharks held on, the less likely the Dragons looked like scoring, and a brilliant 70-metre break from prop Andrew Fifita relieved the pressure.

Shortly after, Shane Flanagan’s side scored their second four-pointer through Wade Graham in the 57th minute.

Carney brilliantly kept the ball alive on the final tackle with a popped pass to Jeff Robson, and the halfback’s perfect grubber kick into the in-goal area was pounced on by the former Penrith utility to the delight of the home supporters.

The Dragons thought they had pulled a try back from Jason Nightingale in the 70th minute, but his left foot was adjudged to have touched the line.