North Queensland Cowboys fell to a third defeat in a row to further harm their top-four chances in the NRL as Sydney Roosters left Allianz Stadium with a 22-10 win.
Last season's premiers have lost form at just the wrong time and it appears likely that they will have to navigate the Finals the long way around with just three regular-season rounds to play.
Ethan Lowe had put the Cowboys ahead after seven minutes as the injury-hit Roosters lost another man when Dale Copley sustained concussion.
Copley's replacement Ryan Matterson levelled things as he bundled over from close range before Shaun Kenny-Dowall and Boyd Cordner helped open up a 12-point advantage at the break in a devastating 15-minute spell.
Kenny-Dowell then turned creator to set Mitchell Latrell away for a fantastic score shortly after the interval to thwart any hopes of a comeback, despite Kane Linnett reducing the arrears with 16 minutes still to play.
Penrith Panthers surged into Finals contention with a brutal 42-6 win over the hapless Newcastle Knights.
After an edgy first half ended all square at 6-6, the Panthers mauled their opponents after the break, running in 36 unanswered points.
Dallin Watene-Zelezniak scored two of the six second-half tries, putting the Panthers seventh with three games to go, two points clear of ninth-placed New Zealand Warriors with huge games against Wests Tigers (10th, 24 points) and Gold Coast Titans (eighth, 25 points) to come.