A review of Wednesday night's action in the Scottish Communities League Cup quarter-finals, including Hearts' win at Hibernian.
For the second time this season, administration-hit Jambos claimed a 1-0 victory over their Edinburgh rivals when Stevenson struck in style in the first half.
The win means Hearts' name will be in the draw for the semi-final, which takes place at Hampden on Thursday.
Aberdeen continued their resurgence as late goals from Andrew Considine and Jonny Hayes sent them into the semi-finals despite playing with 10 men for the bulk of the 90 minutes in a 2-0 win over Motherwell at Fir Park.
Considine was only on the pitch because right-back Joe Shaugnessy had been sent off for a reckless challenge on Zaine Francis-Angol but he headed home from Jonny Hayes' 83rd-minute corner.
The Dons, who moved into second place in the Scottish Premiership on Saturday, also lost Clark Robertson to injury to leave Peter Pawlett and Hayes as makeshift wing-backs but they showed immense resolve and the Irishman ran clear after a Motherwell corner in injury-time to seal victory.
The game looked to be heading to in extra-time when referee John McKendrick ordered a Stevie May free-kick to be taken again for encroachment by Nacho Novo who was booked for his troubles.
May's second effort from 25 yards was spilled by Morton keeper Nicolas Caraux and McDonald pounced to bundle the ball over the line to send the visiting fans into raptures and the home supporters into rage.