"It's probably the poorest we've played since I came back to Hearts," he told BBC Radio Scotland's Sportsound after the Scottish Premier League match.
"We've just got to say that on a day we haven't performed we can still come here and get a point.
"To be fair to Hibs, they never let us settle and we didn't get our game going at all.
Driver (centre) edged Hearts in front before Hibs claimed a draw at Easter Road
"We've been playing with Ryan McGowan as the nearest man to Sutton but it didn't work out."
Andrew Driver profited from a dreadful headed back-pass from Alan Maybury to shoot Hearts in front, but Leigh Griffiths levelled just before the interval.
Hearts struggled to create much in front of goal, but McGowan will be wondering how he missed a wide-open goal with a header from six yards after Hibs keeper Ben Williams completely missed a corner kick.
McGlynn suspected his players had failed to heed warnings about complacency following their 5-1 Scottish Cup final win against Hibs in May and their winning start to the season against St Johnstone last weekend.
"Last week we came out of the blocks, and this mental attitude of thinking it was a matter of turning up by virtually everyone, it kind of backfired," McGlynn explained.
"Maybe mentally we did not apply ourselves in the proper manner.
"If Hibs were ever going to have a reaction it was going to be today.
"They were beaten 5-1 two games ago really by their old rivals in the Scottish Cup final, so if they were going to have any fire in their bellies it had to be for this one because they had a poor performance last week.
"They had to be up for it and it worked against us.
"We didn't quite match that and yet they still couldn't beat us."
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