The return of halves Daly Cherry-Evans and Jamie Lyon could not stop Manly slumping to a 30-26 defeat to North Queensland in Townsville on Monday night - their seventh straight NRL loss.
A try-scoring double to Kiwi backrower Jason Taumalolo helped the Cowboys (3rd, 10-5) remain in touch with the top two.
It was the home side's 10th straight home win, a record stretching back to the end of last season.
While it was an impressive return from Cherry-Evans, which included a first half try, he also had a 73rd minute effort disallowed before his deft kick set up a Lewis Brown four-pointer in the dying minutes to reduce the deficit to 30-26.
Sea Eagles' Addin Fonua-Blake bagged a second half double in five minutes (54th, 59th) after fellow reserve forward Siosaia Vave (46th) crossed and suddenly Manly led 22-18 with 20 minutes left.
But the luckless Eagles couldn't hang on.
NSW prop James Tamou (65th) bulldozed over and hulking backrower Taumalolo bagged his double (68th) to give the hosts a 30-22 lead.
Manly - boasting a nine-strong injury list - had plenty of new faces in their side, and it showed early.
The Sea Eagles looked out of sorts with unfamiliar combinations, leading to unforced errors and plenty of frustration as North Queensland stormed to an 18-4 halftime lead.
North Queensland scored two tries in seven minutes to finish the first half strongly.
Along the way North Queensland's Johnathan Thurston overtook Manly's Graham Eadie (1,917pts) at sixth in the all-time point scorers.
It was the Cowboys' fifth straight win over Manly, who have all but let their finals hopes slip.