Morton's relegation worries increased after they slipped to a disappointing 3-0 defeat to Ross County at Cappielow Park.
The visitors opened the scoring after 34 minutes when Alexander Bone notched his 13th league goal of the campaign.
Young defender Martin Canning doubled the advantage six minutes later when he scored his first goal for the club.
Bone scored his second of the night to make it 3-0 on the stroke of half-time.
Morton's problems were compounded when Brain Kerr was dismissed for a second bookable offence with six minutes remaining.