JOSH Dugan's long right arm grabbed two valuable premiership points for St George Illawarra in a gripping NRL arm-wrestle at WIN Stadium.

Monster Panthers winger Josh Mansour looked to have given Penrith a hard-fought victory when he scored in the 73rd minute to put his side ahead 12-8, before the lanky Dugan beat some fatigued Penrith defence to reach out and slam the ball down one-handed on the line to set up a 14-12 win.

The first 40 minutes failed to produce a try, with the Dragons heading into the sheds 2-0 up courtesy of an 11th-minute Gareth Widdop penalty.

Jamie Soward levelled the scores three minutes after the break, before former junior Kangaroo Euan Aitken finally broke the try drought for an 8-2 lead to the home side.

Penrith, which lost its creative forward Bryce Cartwright to a badly dislocated thumb in the first half, levelled up again when off-season recruit Peter Hiku crossed for his fourth try in as many games for his new club in the 61st minute to set up a grandstand finish.

The Panthers were rewarded for ignoring two opportunities to snap a field goal when Mansour - who had another powerful running game with a massive 228m - crossed wide out, but Soward missed a difficult conversion.

The Dragons raised one last roll of the dice with Dugan, their most dangerous weapon with more than 200 running metres, showing his class to score the winner.