Newcastle captain Kalyn Ponga failed to back up from Wednesday night's State of Origin opener with a lingering ankle injury and his side badly missed their star fullback at Jubilee Oval on Friday.
The Knights' attack was directionless and they made just three line breaks all night, taking until the 70th minute to score their only try through Kai Pearce-Paul.
In contrast, the Dragons had no such concerns, with Gutherson their energiser bunny from the first minute til the last.
While Parramatta might have drawn the best out of Gutherson, there is little doubt the 30-year-old's communication and workrate at fullback are keeping the Dragons dreams of a top-eight finish alive.
Shane Flanagan's men were by no means polished - Valentine Holmes and Tyrell Sloan bombed late tries too - but their ability to fight and scrap in games will ensure they are a chance towards the back end of the season.
Halfback Kyle Flanagan was the architect of the Dragons' opener when he took advantage of some lax Newcastle defence to send Jaydn Su'A over the line in the 20th minute.
Su'A was subbed off straight afterwards and did not return, with the would-be Maroons forward suffering a suspected ankle injury.
But it didn't knock the Dragons off course with Shane Flanagan's pack finding plenty of joy up the middle.
First a rampaging Jack de Belin run was the catalyst for the workaholic Gutherson to cross before Damien Cook sent man mountain Loko Pasifiki Tonga over for his first NRL try.
St George Illawarra had an 18-0 lead at halftime to condemn the listless Knights to a seventh game this season where they failed to score in the first half.
The Dragons threatened to inflict more misery on O'Brien's struggling side with rugby sevens convert Nathan Lawson impressing with his work from the backfield on his NRL debut.
Lawson, who played outside Valentine Holmes on the left wing, finished the evening with 176m from 17 carries and did not look out of place.
Holmes kicked a 62nd minute penalty goal to improve the Dragons' buffer, with the Knights finally scoring through Pearce-Paul after 69 minutes.
The Knights could have more headaches, with Leo Thompson and Tyson Frizell placed on report.
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