Manly have denied Cronulla a top four finish and dented their NRL premiership aspirations with a 14-12 win at Remondis Stadium on Sunday.
The Sharks went into the game with a simple equation – win and snare fourth spot – but now face a sudden death semi-final next weekend.
The result ensured departing coach and Manly legend Geoff Toovey was given a fitting farewell.
A Tom Trbojevic try in the 68th minute gave the Sea Eagles the lead and they were forced to repel several Sharks raids in the last 10 minutes.
The Sharks enjoyed 60 per cent of possession and forced Manly to make 123 more tackles.
They had a mountain of opportunities, being tackled 59 times inside Manly’s 20 metre zone and five times they got over the line but were denied by the video referees.
The Sharks dominated the first half but still went into the sheds down by two.
They bombed a plum opportunity when Michael Gordon and Paul Gallen got in each other’s way when all they had to do was fall on the ball after Trbojevic spilled a Jeff Robson bomb.
The Sharks caught the Manly defence napping when they went down the blind side and Wade Graham barged over to give them an 8-0 lead.
Their advantage was reduced to two when the Sea Eagles were piggybacked down field by two penalties and Jesse Sene-Lefao carried three defenders over the line.
The Sharks further paid for their ill discipline as two Kieran Foran penalty goals gave the visitors a 10-8 lead at the break.
Sharks winger Valentine Holmes was denied what would have been a contender for try of the year when he was ruled to have knocked it on 100 metres back down field on his own try line.
The home team took back the lead when a Gallen offload put Manly on the back foot and Gerard Beale found a hole on the right edge.
But a 100 metre effort from the Sea Eagles allowed them to snatch the win. Departing second-rower Justin Horo took an intercept on his own line and floated the ball to Trbojevic who sprinted away to score in the right corner.