A four-try second-half blitz saw Shellharbour overturn an eight-point half-time deficit to overwhelm Albion Park 28-14 at Centenary Oval on Sunday.
The Sharks came to life in the second stanza after a lacklustre first half in which they were outgunned by the young Eagles, who led 14-6 at the break.
Coach Dave Walsh praised the way his players turned around a first half plagued by poor discipline and incomplete sets.
"We made it really hard for ourselves in the first half with poor discipline on the fourth and fifth tackles," Walsh said
"We spoke about that at half-time and rectified it pretty well.
"We just played a patient pretty sort of game [in the second half].
"We got a few double deals [repeat sets], which put a bit of pressure on them and we were lucky enough to get the result."
The Sharks started the match strongly when back-rower Ryan Schuster barged over from close range during the opening five minutes for an early 6-0 lead.
The Sharks failed to complete a set after the kickoff, which allowed the Eagles to seize the initiative through centre Sean Jenkins, who dragged several defenders over the line to level the scores at 6-all.
The Eagles remained on top for the rest of the half and, when young winger Blake Jones latched onto an intercept and ran 60 metres for a try, an upset appeared on the cards.
The Eagles backed it up through hooker Dean Gray, who dived over from dummy-half minutes later for a 14-6 half-time lead.
It was a different Sharks outfit that took the field in the second half on the back of five-eighth Jai Dormer's relentless kicking game, which kept the Eagles under the pump for rest of the match.
The pressure of repeat sets told when substitute Justin Rodrigues strolled over from a Schuster offload to cut the lead to two at 14-12.
Rodrigues crossed again minutes later when a clever dummy allowed him to score untouched from close range for a 18-14 lead.
Winger Blake Stratton got in on the act, winning the race to a Dormer grubber into the Eagles in-goal before Hans Schuster strolled over from close range to cap the 28-14 win.
Elsewhere in the league Gerringong Lions handed Milton-Ulladulla a 38-10 defeat at Mick Cronin Oval, Berry notched a 30-4 victory over Port Kembla at Berry Showground and Kiama defeated Nowra-Bomaderry 36-23 at Nowra Showground.