The Dons lost Joe Shaugnessy to an early red card for his challenge on Zaine Francis-Angol but were able to hold out the Well before scoring twice in the dying stages through Andrew Considine and Johnny Hayes, delighting the boss.
"They have really answered up when the odds were stacked against them. We said to the players at half-time that they needed organisation, guts, character, everything you need to win the game, but the biggest thing was having a belief," he said.
"To go so long with 10 men was always going to be a concern and with Clark (Robertson) going off (with an injury) as well, we only had one defender on the bench.
"It was gutsy, real guts and determination and a bunch of boys determined not to accept anything other than us getting into a semi-final."
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