In a seesawing match where the lead changed multiple times, Olakau'atu was able to seal the victory in the 77th minute after plucking an Eels offload out of the air to cross under the posts from 20 metres out.
The try came against the run of play, with the Eels in midst of mounting a tremendous comeback and meant a 78th minute try to Maika Sivo - his second of the night - was merely a consolation.
Played at 4 Pines Park to kick off Multicultural Round, the Sea Eagles started the game well, with Reuben Garrick opening the scoring in the seventh minute.
Tom Trbojevic then scored the first of his two tries in a high-scoring match, before his side seemed to switch off mentally and fell away in defence, allowing Parramatta to run in two quick tries for the visitors to go into the half-time break trailing 14-10 after a poor showing to start the game.
The first half was a game of two halves within itself, with Manly utterly dominating the first 20 minutes, before errors crept into the game and the Eels returned serve.
The second half was much the same template, with the Sea Eagles playing well in the first half despite letting Eels captain Gutherson cross for his second try in the 43rd minute.
The home side scored three tries to seemingly be in control of the match, before the Eels again fought back to set up an epic ending to the match.
Parramatta captain Gutherson tried his best to lift his team with his two tries halting the momentum that was building against his side, while Sea Eagles five-eighth Josh Schuster impressed with three try assists in his first game of the year.
The result sees the Sea Eagles remain at the top of the ladder for now and leaves the Eels still chasing their first win.
Story first published by: NRL.com