Jamberoo blew a perfect chance to climb into fourth spot with Saturday's surprise 30-18 loss to wooden spoon favourites Port Kembla at Noel Mulligan Oval.
The Superoos recently snapped a four-game losing slide with impressive wins over Milton-Ulladulla and Gerringong and, in the process, jumped back into final five contention.
Most Group Seven pundits expected the Roos to make it three in a row at Port's expense, but the last-placed Blacks had other ideas.
The home side's enthusiasm and commitment to the task belied their position on the ladder, prompting captain-coach Mark Simon to declare Port capable of more upsets in the run to the finals.
"That's our plan," the veteran playmaker said.
"Obviously it's disappointing that the semis are out of reach because we had that as a goal, but our plan for the rest of the year is to make it hard for the other teams.
"We want them to know they've played us and that we could've been there as well."
A win for Jamberoo would've put them in touching distance of the top three, given that Nowra-Bomaderry and Berry-Shoalhaven Heads both lost on Sunday.
Port were in a statement-making mood against the Superoos, building an 18-0 half-time lead.
Jamberoo hit back with two tries in the second half, but the Blacks re-grouped and finished strongly to claim just their second win of the season.
Centre Christian Kupenga scored two tries for Port and Simon kicked five goals.
"We used the wind to our advantage in the first half to get a good lead and luckily for us it dropped off a bit in the second half," Simon said.
Milton-Ulladulla celebrated their fourth win of the season after Saturday night's 40-22 defeat of Albion Park-Oak Flats at Mollymook Oval. Mitch Simmington and Jimmy Patterson scored two tries apiece for the Bulldogs.