But, after the defeat to Boro on Sunday, the tactics employed by the Northern Irish boss came under scrutiny for the first time.
O'Neill has had a habit this season, despite signing two naturalised full backs during the summer, of playing players out of position in the back line.
Nigel Reo-Coker has been switched to right back on numerous occasions, whilst no-nonsense centre back Carlos Cuellar has been utilised in both full back berths.
Reo-Coker was exposed at Newcastle in that role recently but he cannot shoulder all of the blame. It simply isn't his position.
Fans must have been shocked to see Carlos Cuellar come back out for the second half against Middlesbrough.
The Spanish defender had a torrid time in the first 45 minutes as every pass he played seemed to be misplaced.
Nicky Shorey must have been wondering exactly why he had signed when it was he who was taken off and not Cuellar in the second half.
Credentials
The former England left back was replaced with Marlon Harewood.
Fair enough, Villa were looking for attacking options and sacrificing a defender is not unusual in such situations.
But, Villa continued to play a flat back four with Reo-Coker again pushed back to right back and Cuellar switched to the left side of defence.
It made no sense but, amazingly, it wasnt a shock.
Fans have lost count of the number of times O'Neill has moved midfielders into defence and taken off the naturalised full backs.
Shorey and Young must be doubting their managers faith in their credentials and who would blame them.
Villa must play to their strengths, but how will they ever reach their full potential with players playing out of position.
The starting line up has been consistent, now we need confident and clearly defined full backs and no more strange substitutions.