There is an old saying my fantasy league - never trust a Hammer.

No, that isn’t a throwback to the original, 14th century meaning of the word cockney, but rather a homage to how West Ham have an incredibly curious knack of doing exactly the opposite of whatever you expect - and never has that been truer than under David Moyes.

Much to the detriment of fantasy team selectors around the globe, the Irons are the kind of side to lose 3-0 one week to the Premier League’s resident whipping boys, only to follow it up the next by giving a member of the Big Six a run for their money.

Just take the start of Moyes’ first reign in east London. After a 4-0 defeat to Everton, West Ham responded with a narrow 2-1 defeat to Manchester City in which they initially lead at the Etihad, before beating Chelsea 1-0 and holding Arsenal to a scoreless draw. By way of a 3-0 victory over Stoke, that was then succeeded by losing to Newcastle and drawing to Bournemouth, conceding three goals in both outings.

We’ve seen the exact same pattern at the start of this season; after looking frightfully short of ideas in an opening day defeat to Newcastle, the Irons impressed in a 2-1 loss to Arsenal, before unexpectedly hammering Leicester and Wolves by scoring seven goals without reply and then drawing with Spurs and City.

In fact, looking through the annals of Premier League history, West Ham’s win percentage is better against Chelsea and Tottenham than Aston Villa, Stoke or Bolton.

And specifically throughout Moyes’ two stints in charge, 27 of the 61 points he’s won in the Premier League have come against sides to finish in the top nine in at least two of the last three seasons (Big Six plus Wolves, Everton and Leicester). West Ham’s average against those teams is a point per game; versus the rest of the league made up of considerably inferior opposition, it’s just 0.36 points per game greater.

That is why, as impressive as West Ham’s recent form as been, and as likely they are to at least produce a commendable performance against reigning champions Liverpool this weekend, the real test for Moyes is just around the corner.

Michail Antonio scores a bicycle kick against Man City

After Saturday’s trip to Anfield the Irons face two early contenders for relegation in Fulham and Sheffield United and while the fixture list gets a bit tougher again after that, the headline takeaway is that they’ll face just four members of the aforementioned nine-club cabal between the start of November and mid-February, an 18-game stretch.

In theory, that should be the period in which West Ham’s season truly starts to take shape, when obtainable points are up for grabs pretty much every week and considering their already solid start to the campaign, when fans can dare to consider the possibility of sneaking into contention for Europe.

But if history tells us anything, it’s that you can never trust a Hammer - and while that may seem like a facetious generalisation needlessly undermining what is in reality a strong run of results, it’s also a cautionary reminder that impressing against the top clubs has never been a problem for West Ham. A lack of consistency against the lesser teams, on the other hand, is often what’s held them back.

For Moyes’ second stint as West Ham boss to be a success, that is what he’ll need to devote most of his energy into turning around. Part of the issue is tactical and certainly throughout the Scot’s tenures, intrinsically linked to how the team is set up.

Manuel Lanzini celebrates scoring against Tottenham

Moyes’ tactics work fantastically well when West Ham have the right to sit back and hit better sides on the counter, but when the obligation is on them to take the game to weaker opposition, they lack the same effectiveness. Either neither team seize the initiative and thus cancel each other out, or the Irons invite unnecessary pressure on themselves and eventually pay the price.

That rings doubly true for Moyes’ current 5-4-1 system which, especially in combination with Michail Antonio as the lone striker, allows for natural opportunities to hit teams on the break but doesn’t put West Ham’s most dangerous players in dangerous places when they’re dominating the ball.

How exactly Moyes remedies that remains a matter of debate, but with the likes of Said Benrahma, Andriy Yarmolenko, Sebastian Haller, Robert Snodgrass and Manuel Lanzini still awaiting their first Premier League starts of the season, the potential is certainly there to change the shape of the team to something a little more adventurous. Mark Noble offers a different option in midfield as well, should Moyes feel a third man is needed to help retain the ball against lesser sides.

But considering how historic a trend this is for West Ham, it comes down as much to mindset as circles and crosses on the chalkboard, and mentality is something much harder to change. While West Ham often appear determined to prove they’re worthy opposition for any top Premier League club, they equally often appear almost completely disinterested in showing they’re a level above the sides they should be routinely beating.

Quite where that psyche stems from is one of those chicken-and-egg scenarios (or should that be cockerel and egg), but for Moyes to truly take West Ham to the next level, he needs to ultimately find a way of stamping it out, even if it does come at a cost of fewer impressive results against the big teams. As enjoyable as the Irons’ recent results have been, this constant cycle of overperforming as underdogs and underwhelming as favourites needs to come to an end.