I was there that day , and in fact the player who scored the try on the 7th tackle comes from my home town of Moree so after he retired I asked him about it, his words as follows .
“ it was the last tackle , and we tried the short side but got tackled the player got up , looked at the ref who was waving his arm for the last tackle so with the Manly defenders just standing there thinking it was a scrum ( not a handover back then) I was passed the ball and just strolled over for the try ,I knew , the players knew , it was on the 7th tackle”
It changed the game and was very much part of the reason your side won.