The premiership race has been thrown wide open with potential season-ending injuries to three of the four competition heavyweights derailing their respective finals campaigns.

A day after South Sydney's season flashed before them with Greg Inglis limping from ANZ Stadium with a potentially serious knee injury, the Cowboys and Roosters have been dealt blows of monumental proportions with Mitchell Pearce, Jared Waerea-Hargreaves, Michael Morgan and James Tamou all suffering potential season-ending injuries on Saturday.

While the Roosters moved to the top of the ladder and a step closer to clinching their third consecutive minor premiership with a 12-10 victory against the table-topping Broncos, it began in disastrous circumstances with form front-rower of the competition Waerea-Hargreaves forced from the field in the 12th minute with a knee injury.

The news didn't get much better for the Roosters with NSW Origin halfback Mitchell Pearce also joining the growing round 24 casualty list when he left the field in the first half with a suspected hamstring tear after an innocuous incident stretching out to catch a ball with the tryline wide open.

The injury to Waerea-Hargreaves is a devastating blow for the Roosters given the Kiwi international's rich vein of form over the past few months, however the tri-colours are still holding out hope of welcoming back Pearce at some stage in the finals series.

The Roosters, who notched up their 10th straight win, played the final 12 minutes of the game with just one player on the bench when Kane Evans was taken from the field in a sorry state following a head clash with Broncos centre Justin Hodges.

Across the ditch another of the NRL's leading contenders flexed their muscle to claim victory, but it came with similar consequences to the Roosters as the Cowboys also lost an influential play-maker and front rower.

James Tamou (neck) and Michael Morgan (ankle) both left Mt Smart Stadium on stretchers in the Cowboys' 50-16 win against the Warriors, taken to hospital with their hopes of playing finals football under a dark cloud.

The Rabbitohs insist they won't know the full extent of Inglis' injury until Monday, however they remain optimistic the fullback will play a part in their title defence.

The Roosters' victory has created a logjam at the top of the ladder with the Broncos and Cowboys sitting alongside them with 36 points, six points clear of South Sydney and the Cronulla Sharks on 30 points.

The Roosters registered first points of the match through the boot of James Maloney and looked to have also scored the first try when Blake Ferguson dived on the loose ball from a Maloney kick.

However a lengthy video referee review highlighted a little knock on from Brendan Elliot in the ensuing mid-air contest, denying Ferguson a four-pointer.

The Roosters didn't have to wait long to make amends with Elliott capitalising on an overlap to give his side an 8-0 advantage into the sheds.

The Broncos didn't look like scoring in the first half, but they didn't waste time making up for their lacklustre opening with Jordan Kahu finishing off a backline play to reduce the deficit to two points after 47 minutes.

In front of a crowd of 19,137, the Roosters responded swiftly with Boyd Cordner diving on a Maloney grubber after Kahu made a meal of it in his own in-goal to take a 12-6 advantage.

But a grandstand finish was set up when Corey Oates showed off his acrobatic ability in the corner to reduce the margin to just two points with 20 minutes remaining.

Despite a shortage of troops, the Roosters showed plenty of resilience to hold out a resurgent Broncos outfit to claim their 17th win of the year.