"If you want to think that having Christmas Day off meant that we defended like that, or that's why we conceded four, that's fine," Pearce told the City website.
"But I know in my own mind and heart that's not the case. The players did not play particularly well, some were awful - that's why we got beaten."
"They will come away from Wigan very disappointed at their performances, which in some cases were uncharacteristic," added the City boss.
"They will learn from it, I will learn from it, but some of the basic errors came as a shock to me."