Not since May 2019 has last spot been occupied by the Panthers, who took a step backwards after last week's breakthrough win over the Sydney Roosters.
"The ladder doesn't really matter until July or August, or something, but I guess it's a talking point," said Panthers coach Ivan Cleary following Saturday's defeat.
"When you only win two games, you're going to be down there somewhere."
The four-time reigning premiers showed glimpses of their best early in the second half but a 14-0 halftime deficit proved too big a hurdle to overcome.
Haumole Olakau'atu poured cold water on Penrith's hopes of a comeback, beating Dylan Edwards to Daly Cherry-Evans' kick and scoring with 15 minutes to play.
It was a three-score game when Tolu Koula crossed down the right minutes later.
"Pretty disappointed. It's not good enough, to be honest," said co-captain Nathan Cleary.
"There were definitely periods where we felt like we were gaining some momentum but just gave it away way too easily through errors and penalties."
Penrith are now 2-6 to begin their fourth-straight premiership defence and the season will only become more difficult to salvage when stars are lost to State of Origin duty in the coming weeks.
But coach Cleary still believes there is enough time to make a run at the top-eight.
"Absolutely," he said.
"We've just got to play better. It's not rocket science. To win NRL games, you've got to play better for longer.Â
"We know how to do that, but unfortunately this team to this point, we haven't done that often enough."
The Panthers would admittedly be second-last had Parramatta not received two points for the bye this weekend.
But that will be cold comfort for Cleary's side, who once again put themselves under pressure in the first half at CommBank Stadium.
Penrith gave up an offside penalty, a set restart and then a high-tackle penalty through Casey McLean ahead of Reuben Garrick's opening try on the right edge.
It was a very tough night for McLean, with the Panthers still clearly struggling to adjust to their latest round of personnel changes this season.
After Penrith's Scott Sorensen threw the ball into touch trying to find winger Tom Jenkins, Manly strolled down the other end and Trbojevic threw the last pass for Tommy Talau to score the visitors' second.
It was a strong return from a three-week knee injury lay-off for Trbojevic, who finished with 181 metres and looked comfortable running and changing direction.
"It was great to have him back on the park," said coach Anthony Seibold.
Nathan Cleary's 40/20 kick pulled Penrith back into the game after halftime, with recruit Blaize Talagi crashing over from dummy half to continue good signs as five-eighth.
A one-two on the right helped Izack Tago to Penrith's second try shortly thereafter.
Some 16 penalties were blown, making for a stop-start affair with three players sin-binned.
Sorensen and Manly forward Siua Taukeiaho sat down for what looked mild shoulder charges as the NRL continues to make a point of policing dangerous shots strictly.
Panthers winger Paul Alamoti also went to the sin bin for a professional foul, helping Manly move six points clear with a penalty goal.
Olakaua'atu put the Sea Eagles on the path to victory minutes later and sent a timely reminder of what he could do for NSW this Origin series.
"I don't normally get too excited in the box but I got excited tonight on that try," Seibold said.
"He's some sort of player, Haumole."
15°C