Morton booked a Scottish Cup fifth-round clash against Dundee after Peter Weatherson's hat-trick helped them thrash Turriff United 6-0.
The hosts' early forays saw Weatherson twice came close with his head inside 16 minutes. Team-mate Archibald Campbell fired over the bar soon after, while David O'Brien forced a save out of visiting goalkeeper Stephen Coutts.
Weatherson opened the scoring with his foot eight minutes before the break, powering home from the edge of the box to give Morton a deserved lead.
Turriff's woes deepened a minute before the interval as defender Ross Anderson fouled Michael Tidser inside the box, and the midfielder, who scored twice in Morton's 3-0 replay win over Albion, had no problems dispatching the penalty.
Weatherson turned provider for Tidser's second goal on 63 minutes, the latter drilling past Coutts from 25 yards.
Peter MacDonald then extended the home side's advantage with a headed goal from point-blank range. Weatherson's second and third of the evening swiftly followed, both goals coming within three minutes of each other.
His second strike was a cool close-range finish while he completed his treble by rifling home from 12 yards.