Following a half-time rollicking from their manager, Craig Gilbert, Thornton got their act together after the interval and by the end ran out deserved winners.
And it was top scorer, Ben Anthony, who opened the scoring in the 61st minute when he shot low past Blair Penman after being cleverly set up by Garry Thomson.
Thomson doubled this lead in the 73rd minute with a fantastic volley from 15 yards that smashed off the underside of the crossbar and over the line with the referee having to glance over to his linesman, who had a much better view, to check that the goal should stand.
Three minutes later Daniel McNab, as he had done the previous Saturday, curled in a beauty from the left before celebrating in style with friends and relatives behind the goal.
Tam Hampson converted Stuart Gibb’s 89th minute cross for a late consolation for the visitors but it was too little too late allowing Thornton to make it into the third round draw for the Macron Scottish Junior Cup.
GI Joinery Hibs’ Man of the Match: Daniel McNab
Thornton Hibs: Costello, Ford, Robertson, S. Drummond, Shields, Coleman, D. Anthony, Orrock, B. Anthony, Thomson, McNab. Subs: Keatings, Crichton, Cooper, Adam, Warrender.
Rosyth: Penman, Henderson, Lawrie, Paterson, Prattis, Butryn, Queen, Macmillan, Hampson, Page, Johnstone. Subs: Cameron, Ogg, Gibb, Sibanda, Robertson.
Referee: Mr S. Gill.