Morton have been a difficult opponent for Dunfermline in recent years.
There was an ease with which they took a two-goal lead in this one, through first-half goals from Craig Wighton and Lewis McCann sending them on their way.
Robbie Crawford pulled one back late on and Michael O’Halloran restored their advantage to seal the Pars’ first win over Morton in seven attempts.
The victory moves Dunfermline up to fourth in the Championship, three points behind leaders Dundee United.
Dunfermline take an early lead
Dunfermline took the game to Dougie Imrie’s side from the off and went close in the opening minutes when Josh Edwards’ shot was deflected wide.
The opener came inside 10 minutes when Wighton converted Joe Chalmers’ corner, his third of the season.
Wighton was involved again when Dundee loanee Tyler French was robbed and the Pars striker laid off the ball for McCann in a lovely one-two before McCann’s 30-yard effort came crashing off the underside of the bar.
The Pars continued to dominate and were rewarded on 27 minutes when Ewan Otoo burst out of defence to link down the left, eventually leading to Edwards’ low cross being tapped in by McCann.
That was the 22-year-old sixth goal in nine appearances this season and he should have had his seventh just before half-time.
Edwards’ defence-splitting pass on the counter found Wighton who squared for the unmarked McCann but he put it over the bar.
That followed a decent spell of pressure for Morton but they failed to register a shot on target in the half.
Morton start second half brightly
Morton emerged from the break with a renewed purpose and should have done better with a chance a few minutes after the restart when an unmarked Cameron Blues hooked his shot wide.
That momentum was disrupted when French went down to receive treatment for a lengthy period of time and was eventually stretchered off.
His replacement Darragh O’Connor lasted only five minutes before he was taken off injured as well.
Dunfermline got a grip once more and a Ben Summers shot was saved well and McCann dragged a shot wide when he had options in the middle.
At the other end, Morton were still struggling to work the keeper and there were blocked shots from Steven Boyd and Crawford, with Sam Fisher solid in the middle of the Pars back three.
Alex Jakubiak was then introduced for home debut and had two chances in quick succession. The first was saved comfortably by MacDonald, the second was a better opportunity but he pulled it wide.
Owen Moffat, another substitute, was denied his first goal for the club by another MacDonald save after a solo run.
With eight minutes remaining, Crawford pulled one back for Morton from their first shot on target, beating Sharp with a shot on the turn.
It set up a nervy finish but Dunfermline sealed the win through O’Halloran’s goal when he raced on to Jakubiak’s high through ball to finish, his first goal for the club.
Line-ups
Dunfermline (3-4-1-2): Sharp; Comrie, Fisher, Otoo; O’Halloran, Hamilton, Chalmers, Edwards; Summers (Allan 90+5′); Wighton (Jakubiak 68′), McCann (Moffat 73′).
Subs not used: Little, Fenton, T. Sutherland.
Morton (4-2-3-1): MacDonald; French (O’Connor 55′ (Wilson 60′)), Baird, Broadfoot, Waters; Blues, Power; McGrattan (Bearne 72′), Crawford, Boyd (Gillespie 73′); Muirhead.
Subs not used: Mullen, Davidson.
