The Knights need a miracle to make the top eight, but six of their final eight matches are home at Hunter Stadium.
It was an incredible turnaround.
After 34 minutes, Newcastle coach Wayne Bennett - celebrating his 700th first-grade game in the box - would have been wondering whether he'd lost his dressing room, after announcing last week he would leave the club at the end of the season.
Announcing he was departing because he was "embarrassed" about performances - Bennett's players came out on Sunday completely out of sorts.
Rookie Sharks interim coach James Shepherd on the other hand was attempting to retain his 100 per cent record of victories as Jeff Robson, Michael Gordon and Sosaia Feki scored beautiful tries to bring a sizeable Remondis crowd to their feet.
However, the turning point came the set after Cronulla had shot to 18-0 up, with returning Sharks prop Andrew Fifita coughing up possession off the restart.
From there, Knights dummy-half Tyrone Roberts put Willie Mason over to set the wheels in motion for a second-half comeback.
Mason was picked up on the Channel Nine microphones saying "Get the f***ing camera out of my face" after he walked back from scoring - and the Knights all of a sudden meant business.
A lovely Mullen chip kick in the 53rd minute sat up perfectly for Akuila Uate to dot down, and four minutes later Gidley scored a classy solo try from short range.
Mullen put the scoreline out of reach for the Sharks with a runaway try and field goal.
Wade Graham (shoulder) and Paul Gallen (bicep) both returned to the action after suffering second-half injuries.
- AAP