There is possession,and then, there is the nature of that possession, whether it is endless, pretty, passing triangles - (yes, Arsenal, I'm looking at you), or whether it is the sort of press that takes the form of a slow, suffocating strangulation, - interspersed with swift, endless, lethal attacks - (and a team of the sort of quality that can do that for 90 minutes), a tactic that allows the opponent neither space nor time to recover, let alone mount an attack themselves.
Now, this is not taking away West Ham's achievement in devising - and implementing - a successful game plan.
I do not understand - well, I do, he is criticised because he is not young, stylish, sexy, fashionable, modern - the condemnation and occasional contempt with which Moyes is sometimes regarded by media and football commentators alike; yes, he is an old school British manager, but he is one, who - as
@laptech has earlier pointed out - tends to do exceedingly well with understrength and weakened clubs, clubs sometimes threatened with relegation - delivers consistently, sometimes almost entirely against the odds.
By way of contrast,
@Lord Blackadder has commented on a number of occasions of how, while Pep has achieved much, it is only in the context of exceptionally well resourced teams, which has allowed for the purchase of not just quality players, but extremely good (and expensive) players, and in sufficient number to have the sort of strength in depth whereby other teams can only cast glances of longing envy at the bench - let alone the team - that Manchester City are able to name, week after week.