Danny Lennon was more annoyed with the lack of desire shown by his St Mirren players than the size of the 5-0 hammering at home to leaders Celtic.
"We had great belief in trying to match Celtic in terms of their desire and hunger," the manager told BBC Scotland.
"And, if you bring that to the game, sometimes that can be enough to outdo quality.
"But it certainly wasn't today as we didn't bring it for long periods of the game."
Yet Lennon was happy with the way St Mirren were playing until poor marking allowed Gary Hooper to open the scoring and Efe Ambrose to pounce soon after on a mistake by goalkeeper Craig Samson.
"With Celtic hitting top form and us being below par, I've got no complaints about the score," he said.
"But I felt that, after the initial 12-15 minutes, as soon as the first goal goes in and Sammy makes a mistake and holds his hands up for the second one, we just seemed to let that affect us and I felt our desire and our hunger then dropped and we allowed Celtic to dictate the game after."
Lennon, who gave a first-team debut to 18-year-old forward John McGinn as a late substitute, was philosophical about his side's chances against a team preparing for a Champions League meeting with Barcelona.
"There was great belief in the dressing-room prior to the game and that's what happens when the big guns come to town," he said.
"It either goes two ways. You either rise to the occasion and play or you're actually beaten before you go out there mentally.
"If you look at Glasgow Celtic and what they're bringing off the bench. They are bringing internationals and we are bringing in wee John McGinn.
"That's the gulf and the difference between the two clubs.
"Even if you get a St Mirren side that's on top form and you get a Celtic side that's on top form, nine out of 10 times, Celtic win it."
Lennon said he had a job not only to lift his players but remedy his side's poor defending.
"It is a very emotional dressing-room, both players and the staff," said the manager, who pointed out that Lewis Guy missed an early chance to put St Mirren ahead.
"We have a good opportunity for Lewis and we give away poor goals and I spoke prior to the game about us working hard and trying to be more solidified at the back.
"But it is very basic errors that are costing us dearly."