Dundee cruised past Morton into the Scottish Cup quarter-finals thanks to a lethal second-half performance.
The hosts took the lead through Jim McAlister before Michael Tidser poked the ball past Dundee keeper Rab Douglas from close range to equalise.
Lewis Toshney restored Dundee's lead in the second-half before Colin Nish's header extended their lead.
Two further goals, from John Baird and Declan Gallagher, completed the rout.
The home side pressed early on, forcing successive corners from McAlister; Baird's header from the second of these forcing a fine save from Morton keeper Derek Gaston.
Nicky Riley also tested Gaston early on, with a drive which fizzed narrowly wide.
Baird then went close again, picking up on a flick-on from Nish and rifling in an effort from a tight angle which hit the side netting.
Morton were handed an opportunity when Iain Davidson was adjudged to have handled 25 yards from goal.
Martin Hardie's free-kick brought out a great save from veteran keeper Douglas low at his near post.
Dundee finally got the breakthrough as Colin Nish headed a long ball down into the path of the onrushing McAlister, and he calmly slotted the ball left-footed past Gaston.
The Dens Park side's lead lasted barely a minute, however, as Tidser picked up on a loose ball which had ricocheted around the Dundee six-yard box and poked past the despairing Douglas.
However, the home side were still controlling the play, and pinball in the Morton box led to the ball falling to Baird just outside the six-yard box, but the 27-year-old couldn't keep his effort on target.
The Greenock side began the second half in a more enterprising fashion, with striker Peter MacDonald being supplied the ball more often, although unable to set up a teammate.
But it was Dundee who took control of the match, with a burst of three goals in quick succession to put the match beyond Morton.
First, Lewis Toshney headed the ball into the net at the near post from a McAlister corner to put Dundee back ahead.
Colin Nish then headed home at the back post after the lively Nicky Riley volleyed the ball across the face of goal.
John Baird volleyed the ball past Gaston from the edge of the box after picking up on a headed clearance to give Dundee a three-goal cushion.
Morton had not given up however, and Douglas pulled off a great save to tip a left-footed volley from Michael Tidser over the bar.
But young defender Gallagher killed off any faint hopes the Ton had when he rose at the back post to head the ball past Gaston.
Substitute Steven Milne should have made it six for the Dens Park side, but twice his efforts from a couple of yards out were scrambled off the line, before the Morton defence could clear the ball.