Charlie Adam missed a penalty as Dundee went down to a 1-0 Scottish Cup defeat by St Johnstone.
Zander Clark saved Adam's 75th-minute spot-kick after being penalised following an aerial challenge.
The Betfred Cup winners ultimately progressed thanks to Guy Melamed's 20th-minute strike, which earned them their first Scottish Cup win against their Tayside rivals at Dens Park.
The goal came after a long ball down the right channel went over Liam Fontaine's head and got Stevie May in behind. The forward cut it back for Melamed to stroke into the far corner.
The front pair continued to cause problems. May looked unfortunate not to get a penalty when he skipped past Lee Ashcroft and was felled by a desperate challenge.
Melamed was later denied by Adam Legzdins as he tried to go round the goalkeeper, and fired over after again being set up by May.
Several players with top-flight experience had gone out of the home team after James McPake made four changes. The injured Osman Sow missed out while Paul McGowan, Jason Cumming and Christie Elliott dropped to the bench.
Dundee had plenty of first-half possession but were restricted to long-range efforts, although several of them were decent. Adam and Declan McDaid both came close before Paul McMullan hit the bar.
The hosts had the ball in the net five minutes after the break when Danny Mullen knocked home after Clark had spilled the ball following a collision after clutching a corner.
Referee Craig Napier disallowed the goal on the advice of an assistant, presumably for offside, with McPake booked for his protests.
Mullen was soon protesting again after being penalised for a foul on Clark as the ball bounced in the goalmouth.
Callum Booth missed a chance for Saints before Clark found himself on the wrong end of a controversial decision. The keeper raced to the edge of the box to punch clear cleanly and collided with both team-mate Liam Gordon and Mullen with the referee immediately pointing to the spot.
Adam stepped up but Clark pushed his low shot onto the post and gathered the rebound.
Substitute Glenn Middleton missed a chance to put the game out of sight but one goal proved enough for Saints.
