A Michael Gordon penalty right at the end snatched a 16-14 victory for Sydney Roosters which could cost Cronulla Sharks a top-four finish, while NRL minor premiers Melbourne Storm humiliated South Sydney Rabbitohs on Saturday.
Cronulla had a great opportunity to replace Parramatta Eels in fourth when a converted Luke Lewis try brought them level in the closing stages at Southern Cross Group Stadium, with the Roosters a man down after Luke Keary was sin-binned.
It was Trent Robinson's men who came away with the points, though, after Gordon made no mistake from the tee to move the Roosters above Brisbane Broncos and into second with just one round remaining.
Defeat for the defending premiers leaves them fifth and needing the Rabbitohs to beat the Eels next Friday as well as victory in their match with Newcastle Knights two days later to have any chance of making the top four, with the Broncos possessing a far superior points difference.
Isaac Liu crashed over for the opening try and Blake Ferguson showed great strength and swift acceleration to add another after 27 minutes following penalties from James Maloney and Gordon.
Valentine Holmes' converted try cut the Roosters' lead to 12-8 at half-time, but Gordon made it a six-point game with a second penalty.
Lewis burst through a gap to go under the posts and Maloney added the extras with Keary off the field due to a professional foul, only for Gordon to hold his nerve after veteran Sharks captain Paul Gallen was penalised for holding the ball too long right at the death.
The free-scoring Storm sent out a warning to their rivals ahead of the Finals with a brutal 11-try 64-6 demolition of the Bunnies at AAMI Park.
Josh Addo-Carr and Suliasi Vunivalu scored hat-tricks in a one-sided encounter, Tyrell Fuimaono coming up with the Rabbitohs' only try in the second half.
Gold Coast Titans ended a difficult week, which started with the sacking of coach Neil Henry, with a 26-14 loss against Canterbury Bulldogs Cbus Super Stadium.