Ronny Deila insists he never doubted his Celtic players' mettle as they trounced Greenock Morton.
"We had a rough period," Deila said. "We haven't lost so much but we haven't played well, we've had some draws and in cups, you have to win.
"We're in the semi-final again, four times in two years, and will do everything to get the trophy."
Deila added he paid little attention to the criticism directed towards him and his team in the wake of a disappointing run of form that has helped Aberdeen maintain a credible challenge to the Premiership leaders.
"Everybody knows what's in it - there's winners sitting in that dressing room," said Deila. "They hate losing and they hate performing badly. It's about getting the right mentalit,, and that people are calm and focus on the right things.
"I don't think so much about the criticism. I'm as disappointed as everyone else and I'm maybe more critical than people around.
"You get sleepless nights and you have to believe in people around you - I believe in my players and I know what they can do and today they showed a good performance.
"If we continue building on that we will get back to the level we were at before."
Greenock Morton manager Jim Duffy meanwhile bemoaned his side's defensive mistakes in the lead-up to Celtic's early goals, with Leigh Griffiths and Gary Mackay-Steven capitalising to score and Callum McGregor adding a third.
"The work ethic was fantastic but we made errors for the first two goals in particular," said Duffy. "That gave Celtic all the incentive they needed to win the game comfortably.
"I thought we started reasonably well but the first couple of goals were basic errors. Celtic are good enough to create chances without us handing them those opportunities."