Dundee United manager Robbie Neilson told his players they must learn the lesson of their shock home loss to East Fife.
Goals from Aaron Dunsmore and Liam Watt earned the Fifers their first competitive win over the Tangerines since 1972 and first Tannadice triumph since 1946.
Neilson said: “I am just disappointed.
“We had had a decent group stage, having gone to Tynecastle and done well and had two good games after that.
“Then we got that tonight.
“It wasn’t good enough but I would rather it was now than in the league.
“It is important that we try to learn from it and make sure that we don’t get another one like that.
“Performances had been good.
“It was just one of those nights for us.
“We have to look at it and see what we can do better.”