It was, after all, the worst result in the Fir Park club's recent memory, and emotions inevitably ran high after such a sorrowful display.
Lost among the knee-jerk grievances of these swivel-chair critics, though, is the fact that Motherwell are five points better off in the league than they were this time last season, and have won eight out of their 14 matches so far. Cup heartache must also be balanced against the loss of the majority of their team - and nearly all of their pace - during a summer of forced clear-outs. But despite these substantial mitigating circumstances, McCall was willing to acknowledge his naysayers.
"I don't do social networks," he said. "But any criticism I've had is merited because we said we wanted to improve our cup performances and we obviously haven't. It's nice when you get plaudits, slaps on the back, but when things go wrong you've got to stand up and be counted and take the criticism."
McCall showed loyalty to the club in the summer, rebuffing Sheffield United to take the club - however briefly - into Europe and try to maintain second place in the SPFL Premiership. And despite losing his most precocious creative talent, he refused to criticise the board for not replacing them with similar options and maintained he had no regrets about moving on when he had the chance.
"I've had some really nice calls from ex-managers, team-mates saying 'chin up'. Some have said: 'Do you regret not moving on?' but no, the staff and the club and everyone are committed to doing as well as we can in the league," he said. "It [the cup loss] still hangs over us. Football is about winning. The more we do that between now and the end of the season, the happier everyone will be.
"We've got different types of players this season, but we've got five points more," McCall continued, backing his side's recent record. "We've won eight out of 14. With all the players we've lost, they've stepped up to the mark and when we've had to win, we've won. But we lost players who could beat players and create a goal out of nothing. We didn't have them last week on the park."
Steven Hammell, the left-back who has been with the club since he was a teenager - save for a fling with Southend United - was one of last season's stand-outs who stayed, and he winced as he was forced to relive the previous week's anguish. "That's the worst result for me by 100 miles," he admitted. "Nothing comes close. Shocks happen, they do, but that should not be happening. It's the worst I've felt. That's one that will live with me for the rest of my life."
Motherwell have beaten Celtic in the last two encounters at Fir Park - though the Lanarkshire side has changed drastically since then - and Hammell admits that watching the champions tear through a ramshackle Hearts side last week would be enough to worry any side in Scotland.
"That just highlights how good we need to be," he said. "Anything like we played last week will be punished pretty severely. When we won those games [last season] we were playing at a really high level. We've played some of our best stuff. We need to put in one of our best performances, that's for sure."