Luis Lopes, Vicente Besuijen and Leighton Clarkson struck in extra time as Aberdeen eventually defeated spirited Annan 4-1 at Galabank to reach the last eight of the Premier Sports Cup.
The cinch Premiership side looked to be in bother against their League Two hosts after home captain Steven Swinglehurst cancelled out Besuijen’s opener to make it 1-1 at the end of the regulation 90 minutes.
But the Dons made their superiority count in the additional 30.
Aberdeen boss Jim Goodwin made three changes to the side that started Saturday’s 5-0 win over Livingston as Matty Kennedy, Shayden Morris and Jack MacKenzie replaced Clarkson, Jonny Hayes and Hayden Coulson.
The Dons had their first decent opening in the 11th minute when Kennedy tried to jink into the box and get a shot away but he was blocked off by a cluster of Annan defenders.
Despite being second bottom of the fourth tier, Annan were holding their own in the early exchanges and they threatened in the 13th minute when Benjamin Luissint sent a low shot just wide after being teed up on the edge of the box by Chris Johnston.
The Dons went close to taking the lead in the 18th minute when Kennedy’s shot from the angle of the box took a deflection and eluded keeper Greg Fleming but Swinglehurst was on hand to clear from just in front of the goal line.
Annan were growing in confidence as the half wore on and five minutes before the break Tommy Muir hooked a volley off the post after connecting with Johnston’s corner just outside the six-yard box.
The visitors almost netted in first-half stoppage time as Liam Scales headed inches wide from Kennedy’s corner.
Goodwin was clearly not happy with what he had witnessed from his team as he made a double substitution for the start of the second half, with Hayes and Lopes replacing Kennedy and Morris.
The Dons were far more assertive after the restart and Hayes went close to breaking the deadlock when his cross from the left almost dropped in at the far post before being clawed out by Fleming.
The breakthrough came in the 55th minute when Besuijen met a low delivery from MacKenzie and forced the ball over the line from close range despite the best efforts of Fleming to scramble it out.
The goal seemed to have taken the sting out of the hosts’ challenge and Aberdeen almost netted again in the 67th minute when Jayden Richardson fired a powerful shot just over after latching on to a Besuijen cutback inside the box.
But Annan levelled with nine minutes left when Swinglehurst powered home a header from Johnston’s corner to force extra time.
The Dons got themselves back in front when Lopes headed home in the 97th minute from a Clarkson corner. Besuijen then put daylight between the teams when he slotted home a low angled effort from eight yards out just before the end of the first additional period.
Clarkson sealed the Dons’ progress with with a strike from just inside the box with three minutes left.