Firstly, at the start of the season teams are more up for it and you can get caught cold. Secondly, they had their eye on the European ties and making the Champions League.
But the Kilmarnock game last weekend was completely unexpected, I thought that kind of performance had been eradicated. Celtic didn't play with any conviction and Neil was rightly unhappy.
The biggest thing for me is the fact that they are going to win the league, even although Neil or the players won't say that in public.
Sometimes, because they don't have the threat of Rangers, there will be blips like the Kilmarnock game. I wouldn't say it is inconsistency. It is down to the fact that it is a matter of when, not if, they win the league.
You will get off-days, but I don't think it will happen too often and I think Tuesday night's win over St Johnstone proves that the Kilmarnock game was a slip and they are back on track.
Those results can happen in football, it is about how you react to it that counts.
When you have the high of playing in the Champions League, it can be difficult for the players to return to the league when they will know they will win the title.
I think the players answered the critics well with the win over St Johnstone and Neil will certainly be happier with what he saw.
You can see that the fans have perhaps focused more on the Champions League, that is reflected with some of the attendances we have seen at Parkhead recently.
Neil has at times made a few changes to the team and I can understand why he would do that.
But the players then have to take the chance that they have been given and convince him that they should be in contention for a starting jersey on a regular basis and playing in the first team week in, week out.
Sometimes it works for you, sometimes it doesn't.
Neil has tried to rotate his squad and freshen it up at times and it is up to those players who come in to take their chance.
If they don't then he has the perfect answer. He can say to them, 'I have given you the opportunity and you haven't impressed enough'.
All the players will want to play in the Champions League games but, to do that, you must play well in the league games and prove that you are worthy of being in the team.
It will be a hard game for Celtic up at Dundee United this weekend, but they have to approach it the same way as they did for the Motherwell game before they went and won over in Russia against Spartak Moscow.
They have to start with the right tempo. If they get that right, then they will win games.
Their attitude has to be right because, if it is not, then you saw the consequences last weekend; teams are capable of beating you and credit has to go to Kilmarnock for their performance on the day at Parkhead.
If the attitude is right then Celtic will win matches and any talk about slip-ups and inconsistency won't be on the agenda.