Benji Marshall produced his best performance in a St George Illawarra jersey and Josh Dugan grabbed a hat-trick as an injury-plagued Cronulla side were put to the sword 30-0 in Wollongong on Saturday.
The beleaguered Sharks were without 13 of their top-25 playing squad and 2010 Golden Boot winner Marshall took full advantage having a hand in five of his side's six tries in front of a crowd of 12,079.
Dugan gave his hopes of a recall to the NSW Origin side as a right centre a real shot in the arm with two tries before the interval, with Peter Mata'utia and Gerard Beale also crossing for four pointers.
The former Canberra star completed the second hat-trick of his career midway through the second half when he soared above a statuesque Sharks defence to haul in Marshall's perfectly-weighted kick.
Dugan's display will certainly have given NSW coach Laurie Daley food for thought but so would the level of opposition he faced, which was little more than a reserve-grade standard.
But it would be churlish to be too critical of Marshall, in his third game since his shock return to the NRL from his disastrous spell in New Zealand rugby, as he showed glimpses of the class he demonstrated so often in a Wests Tigers shirt.
Mata'utia's 13th-minute opener was created by a sweeping run and pass from the former Kiwi skipper that found Aidan Quinlan in support.
Marshall then set up Dugan's first try with a smart inside ball before producing a no-look pass to gift-wrap his second.
He then delivered a delicious long pass to Gareth Widdop that resulted in Beale charging over the line.
The Sharks were much improved after halftime but were toothless in attack and with playmakers Todd Carney and Jeff Robson on the sidelines, they never really put the hosts under pressure.
Beale added some extra gloss to the scoreline with his second try four minutes from time following a brilliantly regathered grubber-kick from Widdop, handing McGregor his first victory as interim coach.
McGregor said he was delighted with the improvement in his side following Monday's loss to South Sydney and said Marshall's performance didn't come as a surprise to him.
"Just getting better week to week is all I am after at the moment," he said.
"I spoke to them at halftime about their completions rates and challenged them to get over 82 per cent and they got to 85.
"The other challenge was to keep them to zero and we did that and that was pleasing.
"Benji has been showing a bit of class all week and no one has seen it apart from the coaching staff and the players at training.
Sharks coach Peter Sharp said he'd never seen such a lengthy injury list in his long career and said he hoped to have at least 10 players back for their clash with Manly in two weeks' time.
"We just want to be healthy and that has been our sole aim for the last three weeks," Sharp said.
"Let's draw in the sand and let's try and play some good positive footy for the last 10 weeks.
"That will put everyone in a better frame of mind.
"We had 10 or 11 top-line players out today and that is a fair chunk of your squad."
St George Illawarra Dragons 30 (J Dugan 3 G Beale 2 P Mata'utia tries G Widdop 3 goals) Cronulla Sharks 0 at WIN Stadium. Referee: Gavin Badger, Chris James. Crowd: 12,079
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