Morton maintained their advantage at the top of the First Division with a 3-0 victory at Dumbarton.
The last time the two sides met it was The Sons who were 3-0 victors, but Allan Moore's men turned the tables as they dominated throughout.
The deadlock was broken with 32 minutes on the clock when Michael Tidser unleashed a left-foot strike from 25 yards out that flew into the top right-hand corner of the net.
Moore's charges doubled their lead six minutes later through Martin Hardie's header as the midfielder found the back of the net following some good work by Kevin Rutkiewicz down the right flank.
In-form striker Peter MacDonald completed his side's revenge after 81 minutes, heading home Colin McMenamin's cross from the right to take his tally to seven goals in his last six games and leaving Ian Murray's side without a win in their last five outings.