Hearts had been riding a wave of positivity after recent performances from the fresh-faced starting 11 had produced respectable Clydesdale Bank Premier League results and a place in the Scottish Communities League Cup Final.
A lot of that good feeling deflated in front of 14,000 spectators at Tynecastle who witnessed a visiting Kilmarnock team score three goals at the ground for the second time this season; Paul Heffernan matching the early season achievements of his injured striker partner, Cillian Sheridan, by netting a hat-trick.
The Irishman opened the scoring with a close-range header after 36 minutes by getting on the end of a James Dayton cross from the left.
Hearts upped the tempo at the beginning of the second half but soon found themselves in a hole they could not get out of when Heffernan made it 2-0 after the hosts failed to deal with a Dayton corner.
The final score flattered Kilmarnock, who had been clinical in attack, but that did not stop the fans flooding out of Tynecastle with jeers ringing round the half-empty stands at full time.
"All the time with young players it is the same, it is a learning process," McGlynn said. "You have to take the bad games on the chin and get better from it.
"It's a lot easier in games when they're allowed the time to get the ball down in pass it. We're not going to blame the young lads for the defeat, we all have to defend our situation better, but they still have to learn from this."