The Brisbane Broncos were on fire from the start of Thursday's clash with Penrith.

The Broncos escaped a Penrith point-scoring frenzy but may have paid a heavy price with star centre James Roberts carried from the field five minutes from full-time in their 32-18 win at Suncorp Stadium on Thursday night.

When Brisbane added to the punishment of their 22-point first half with the first try of the second term the application of the mercy rule was researched, but inspired by captain Matt Moylan Penrith scored three tries in the space of eight minutes to turn a 28-0 bloodbath into a 10-point deficit with plenty of time still left on the clock.

The adventurous play that had seemed so ineffective for the first 65 minutes for the Panthers continued until the final moments but with every risky pass was the potential for disaster and the home side was able to close out their sixth win of the season with Penrith completing just 56 per cent of their 41 total sets.

The more immediate concern for Brisbane may however be the injury to Roberts who was unable to finish the game after teammate Matt Gillett's swinging leg crashed into his own just below the knee, bringing a premature end to an otherwise brilliant display.

Playing against his third former club in as many weeks, Roberts made the Panthers pay for one of their nine first-half errors to spark his side's first try in the 11th minute before scoring an 85-metre effort of his own seven minutes later after another Panthers mistake.

The Panthers were denied a try to James Tamou in controversial circumstances in the fifth minute when the Bunker overturned the on-field decision of 'try' by referee Gerard Sutton, hooker Peter Wallace ruled to have knocked on in a tackle by Josh McGuire that appeared to have dislodged the ball in a backwards direction.

Whether landing the first blow would have improved the fortunes of a team looking desperately for ways to avoid a fifth straight defeat we will never know but their reaction to Brisbane scoring six minutes later suggested that their already fragile confidence wasn't going to be rediscovered within the confines of 'The Cauldron'.

Coming into the game with the worst completion rate in the NRL through eight rounds with 73 per cent, Penrith couldn't even live up to that standard in the first half, completing just 10 of 19 sets at 53 per cent to continually allow Brisbane to launch attacking raids.

They were invitations that were gratefully accepted as Roberts split Peta Hiku and Isaah Yeo from a scrum on halfway in the lead-up to the opening try for Kodi Nikorima, and Roberts was then the recipient when a dropped ball by Yeo was claimed by Nikorima who sent Roberts on a long-range run to the try-line for a 10-0 lead through 18 minutes.

In the 30th minute a seemingly innocuous Anthony Milford cross-field bomb was snared by Jordan Kahu as Nathan Cleary, Peta Hiku and Waqa Blake all failed to contest it and then showing no mercy for a Panthers seem struggling to keep pace, Alex Glenn sparked a 70-metre movement by splitting the Panthers defence right up the middle before finding Darius Boyd who linked up with Tautau Moga to score in the 34th minute and a 22-0 lead at half-time.

After two narrow victories in the past fortnight the Broncos came out to start the second half full of the type of running that comes with a 22-point lead, answering Wayne Bennett's call to kill off any sense of a Penrith comeback with an energetic start.

Their response was typified by Korbin Sims' high-octane charge to score under the posts in the 51st minute that left him with a broken and bloodied nose and a trip to the sideline but they went through some nervous moments before Gillett crossed in the left-hand corner in the final play of the game.

Where the Broncos played with purpose and energy the more the game wore on, the Panthers looked directionless and second-guessing almost every use of the football but finally found a spark on the back of Moylan's heavy involvement.

Utility Tyrone Peachey provided some energy when he entered the contest but rarely did any play seem to have any meaningful connection to the play that preceded it.

It took until the 65th minute before Kangaroos lock Trent Merrin could twist, turn and reach out to score Penrith's first four-pointer and whether further tries to Moylan and Reagan Campbell-Gillard can in some way re-ignite their finals hopes won't be known until the weeks to come.

Brisbane Broncos 32 (Kodi Nikorima, James Roberts, Jordan Kahu, Tautau Moga, Korbin Sims, Matt Gillett tries; Jordan Kahu 4 goals) def. Penrith Panthers 18 (Trent Merrin, Matt Moylan, Reagan Campbell-Gillard tries; Nathan Cleary 3 goals) at Suncorp Stadium. Crowd: 21,464. Half-time: Broncos 22-0. Holden Cup: Panthers 44-12.