Hearts had been riding a wave of positivity after recent performances from the fresh-faced starting eleven had produced respectable SPL 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."
Time on the ball was certainly something Hearts did not get. A 20-yard Jamie Walker shot was all they could muster on the attacking front from a first half that saw their opponents swarm around the attacking quartet, continually forcing attacks back to the defence for a rethink.
However, rather than heap praise on his side, Killie manager Kenny Shiels took time to praise the efforts of those behind the scenes at Hearts and their insistence on bringing through young players from the academy.
"I don't think Hearts get enough credit," he said.
"People like John Murray [Hearts director of football], I don't think Hearts realise how lucky they are to have someone like that in the development side of the club.
"They know that their long-term planning is really good and I have a lot of respect for that. They want the club run the right way."
Everything fell the right way for hat-trick hero Heffernan. His third goal summed up his afternoon when his generosity was rewarded after squaring to Borja Perez when he could have drove at goal himself, and the ball eventually came back to him to tap into the empty net after Jamie McDonald had stopped the Spaniard's shot.
It was the second hat-trick of his Killie career and helped his side to a perfect three wins from three against Hearts in the SPL this campaign.
"I'm delighted to get the hat-trick," Heffernan said. "It's my job as a striker to finish the chances that are created by my team-mates and today I've done that. Although I think the distance was a combined 12 yards from the three goals.
"I doubt know what it is, but obviously they are a good side, but we just seem to really look forward to coming here. I can't really explain it, they are just a team we always seem to get our noses in front against."