Partick Thistle slumped to their heaviest defeat of the season as Morton came from behind to leave Gary Caldwell still looking for his first win in charge of the Jags.
Hopes must have been high in the visiting camp when Brice Ntambwe’s bullet header from a Craig Slater corner give Thistle an early lead.
The advantage lasted just seven minutes before Jack Iredale and Gary Oliver exchanged passes down the left with the former’s cross tapped home by Oliver.
Strong winds played a part in the second goal but it didn’t legislate for shocking Thistle defending that allowed Bob McHugh to adjust brilliantly to head another Iredale cross into the net before the interval.
Iredale capped a brilliant individual performance by turning provider to scorer when he squeezed a shot beyond Bell at the back post on 55 minutes.
McHugh grabbed his second to make it four.
Michael Tidser piled the misery on Partick with a powerful shot for his seventh goal of the season.