McGregor’s magnificent goal papered over some large cracks against St Mirren.
Celtic have failed to score in six matches this season, have scored fewer in the league than both Hearts and Hibernian, and were blunt again against St Mirren.
It took until second-half injury time for O’Neill’s side to have an effort on target – a tame header from substitute Yang Hyun-Jun. It took a moment of magic from McGregor to turn one point into three.
For large stages of the match, it looked as though it might have been zero.
Conor McMenamin twice went close in the first half, Miguel Freckleton spooned an excellent chance over the bar, and Liam Scales put through his own goal, only to be spared his blushes by an offside flag against McMenamin.
It was put to the former Leicester City, Aston Villa and Republic of Ireland boss that off-field dramas might have affected the Celtic players on the pitch.
“When it was a continuation of not really supporting the team tonight, and it was just ‘sack the board’ the whole way through, there’s an element that it might [affect the team],” O’Neill said.
“I don’t think it helps, but the one thing we don’t lack is unity within the dressing room.”