The Sydney Roosters have recorded their biggest win over St George Illawarra and ended the Dragons' NRL finals hopes with a 42-6 thumping at Allianz Stadium.

Blake Ferguson and Daniel Tupou scored two tries each for the Roosters on Sunday, and Mitchell Pearce and Jared Waerea-Hargreaves were also highly influential as the home side scored just their sixth win of the season.

The Dragons needed to win the last three games of the regular season to keep their finals hopes intact, but were swamped by five second-half tries after trailing 14-6 at the break.

The Roosters dominated early on the back of their powerful forward game and led 12-0 after 27 minutes courtesy of tries to Mitch Aubusson and Ryan Matterson.


The Dragons rallied late in the first half, and a Gareth Widdop try in the 36th minute kept the visitors in touch.

But after halftime, the Roosters continued their recent good form, which has included wins over 2015 grand finalists North Queensland and Brisbane.

After defeating the Cowboys last week, the Roosters have now recorded back-to-back wins for the first time this year.

Pearce took full advantage of his forwards' dominance against a disappointing Dragons side, who had plenty to play for but failed to respond.

Tupou and Ferguson's tries in the second half along with a four-pointer by Aidan Guerra blew the Dragons off the park.

After being recalled following last week's sacking via an injury to Dale Copley, Guerra had a fair game for the Roosters.

Aubusson injured his kidneys in scoring the first try and didn't return.