Dundee Unite 3 Morton 0 (5-1 agg)
Dundee United booked their place in the Premiership play-off semi-final with comfortable 3-0 win over Morton at Tannadice to go through 5-1 on aggregate.
Following a 2-1 win for the Taysiders at Cappielow on Tuesday night, United attacker Simon Murray broke the deadlock in the 52nd minute with a close-range drive.
Recently signed midfielder Wato Kuate drove in a wonderful second from distance in the 64th minute - his first goal for United - before Blair Spittal added a third with a confident finish.
Ray McKinnon's United side will host Falkirk on Tuesday before the away game to their Championship rivals on Friday as they look to get back to the top flight after at the first time of asking.
The Greenock side started the game determined to claw back the deficit and in the sixth minute striker Kudos Oyenuga flashed a 25-yard drive wide of the target after being gifted possession by United midfielder Willo Flood.
The Terrors responded and Thomas Mikkelsen's low drive was saved by Morton keeper Jamie McGowan, before fellow attacker Simon Murray's angled-shot on the turn from 14 yards slipped past the far post.
Another effort from Mikkelsen flew just over the bar before McGowan made a fantastic leaping save from Tony Andreu's header in the 37th minute, after the Ton defence had failed to deal with a long free-kick from Stewart Murdoch.
It was Murdoch's cross from the right into the box early in the second-half which led to goal.
Under pressure from Mikkelsen, Morton skipper Thomas O'Ware headed straight to Murray who rifled it past McGowan from eight yards for his 16th of the season.
With a two-goal deficit in the tie to recover, Morton had to push forward and just before the hour mark Oyenuga headed an Aiden Nesbitt ross over from six yards out.
But it was effectively all over when Kuate, signed last month until the end of the season, delivered a wonder strike.
The 21-year-old Cameroon-born Portuguese midfielder, a former Manchester City youth player, stunned Morton with a thunderous left-footed strike from 30 yards which gave the flailing McGowan no chance, with Spittal volleying in number three in the 81st minute from a Murray cut back.