Cronulla overcame a 14-point half-time deficit with three unanswered tries to get out of jail against North Queensland on Thursday night.
The Sharks were near-faultless in the second half of the 18-14 win, as they took the lead with 14 minutes to play when Sosaia Feki scampered down the left touchline.
Andrew Fifita was immense for the defending NRL premiers, as he turned the match on its head when he was brought back onto the field by coach Shane Flanagan in the 57th minute.
He provided a vital offload for Chad Townsend to cross under the posts with 18 minutes to play and then produced a bullocking run in the lead up to Feki's match winner.
It was typical of Fifita's performance at Southern Cross Group Stadium in his last match before the State of Origin opener for NSW.
He broke through 11 tackles in a powerful display, where he ran 188 metres and regularly carried the defence across the advantage line.
James Maloney scored a try in the 50th minute as the Sharks' second-half effort of just three errors completely contrasted their first.
They had earlier completed just nine of 14 sets in the first half, as they looked set to lose their fourth game at home this season.
Michael Morgan was dominant for the Cowboys early for the second-straight week without Johnathan Thurston.
He skipped at the Sharks' defence to help lay on the first try for winger Antonio Winterstein, then put a cross-field kick high for Kyle Feldt to score in the shadows of half-time for the 14-0 lead.
Scott Bolton and Jason Taumalolo were also difficult to stop up front, before the visitors seemingly ran out of steam in their second trip to Sydney in as many weeks.
Feki's final try turned him from villain to hero in just 80 minutes.
He should have scored the Sharks' opener in the 10th minute when he fumbled a Maloney grubber across the line while unmarked.
He was also nowhere to be seen when Feldt burst down field in the 33rd minute for Ben Hampton to score one of the visitors' three first-half tries.
But it mattered little in the end as the Sharks finished the far stronger of the two sides.