We can go back to the Brighton game on 21st December and since then, Liverpool and City apart we've played:
Brighton Twice, Watford, Arsenal West Ham, Palace, Bournemouth and Norwich,
All but Arsenal and perhaps Palace have been in the bottom end of the table and have been playing perhaps to not lose as a priority, so breaking sides down is harder, so we've also ensured that we preserve a lead rather than go and extend it.
Bournemouth is the only game in that time where we've scored two goals. Against Arsenal and Bournemouth we got pegged back and had to go again. The efforts to do that make scoring goals harder.
Lets not forget that Arsenal, West Ham and Watford were also in transition after replacing their managers. So they also play differently.
None of this is meant as an excuse, but I think it can also explain the mentality of the sides we're facing and how they are having to adapt to play us.
What is also really important to note is that we've conceded 4 goals in the 8 games (again taking City and Liverpool out for now), we're a side that gets wins by keeping things tight. We're not a defensive side, but we're organised.
I'd be worried if we weren't creating chances, we're having a lot of corners and set pieces which are dangerous, so perhaps we need our 3 Centre Halves and big lads like Lunny and McBurnie to weigh in with more from set pieces, but reality is that teams will work on this so its not a given.
I actually think that after the Newcastle game, the run of games against Spurs, Burnley, Wolves and Chelsea will be much more open (and if we can get Man U in there somewhere too it would be good), so we'll probably get more chances to hit sides on the break (Mousse and Ziko will be used more)