The Everton motto, nil satis nisi optimum (nothing but the best is good enough), makes it very hard for any manager to succeed at Goodison Park.

And that now includes their highest ever paid boss, Ronald Koeman, who has been sacked just nine matches into the new Premier League season.

They were just as bad, if not worse, in the Europa League, so where and why has it all gone wrong for the Dutch master and former European Cup winner schooled in Total Football at Ajax and Barcelona?

A key comment circulating around Goodison Park on Sunday, after what turned out to be his final 5-2 defeat by Arsenal was ‘he never really understood our club.'

Koeman never shied away from the fact he would love to return to the Nou Camp as boss one day. He has never fully distanced himself from managing his country too, every time the Dutch job was linked with him.

That was all fine when Everton were winning but meant the fans were never going to give him so much grace, as they did with predecessor Roberto Martinez, when things started to go wrong.

But nine games? That is not the Everton way and is the first time a coach has been dismissed so quickly since Mike Walker’s disastrous 35-match reign 23 years ago.

Koeman, who insisted he could fix things, got 55 all told.

And although he leaves them in the relegation zone, on goal difference, the reason there is an element of surprise is that the men who sacked him, only just backed him to the tune of £140m worth of new players in the summer.

And that is the root of this Merseyside mayhem.

Koeman has recruited poorly, at least based on the start of this season. Whether that is wholly his fault and not partly to down to transfer guru and Everton Technical Director Steve Walsh is debatable.

But it was Koeman who headed the operation, pressing for midfielders such as Gylfi Sigurdsson from Swansea (£45m!) and Ajax captain Davy Klaassen (£25m).

While Sigurdsson is a proven player at this level and could yet prove his worth, Koeman's fellow Dutch countryman is not settling well at all.

Klaassen was even substituted at half-time in the Europa League home defeat by Lyon.

But getting a Koeman hook after 45 minutes is not an unfamiliar fate for some players this season.

While it could be argued it is a sign of decisive management to change a team when things are going wrong, it is an even stronger indicator the manager has not got his tactics or line-up right going into a match.

The half-time switch against Arsenal was the ninth time he has made a substitution after 45 minutes in the 17 games they have played in all competitions to date this season.

And although Koeman can rightly be faulted for trying to introduce too many players in one hit – he signed eight senior players – the biggest mistake was the player he did NOT sign.

Everyone and anyone in football knew Romelu Lukaku was off at the end of last season.

Koeman and the club’s directors cannot be blamed for failing to keep him, but they can for not signing a replacement even half as good.

Why not make getting a new striker in a prerequisite of selling him?

Would they have got the Olivier Giroud deal over the line if they had offered more money, or sold the club to him in a more convincing fashion? Probably.

Is that Koeman’s fault? Possibly.

Could they have signed someone else? Definitely.

Either way, going into the season without your 25-goal guarantee in Lukaku and replacing him with raw Spanish under-21 international recruit Sandro Ramirez and promising England under-20 starlet Dominic Calvert-Lewin was placing too much weight on young shoulders.

If that was all down to Koeman then he has justifiably paid the price by losing his job.

Other recruits look like strong investments. Jordan Pickford could well be the NO.1 for club and country for many years while his fellow England international Michael Keane might well be playing in front of him.

It is when we look at his more attacking recruits the argument to retain him looks less solid.

For even if Sigurdsson and Klaassen come good, can they play in the same side and formation with the returning prodigal son, Wayne Rooney? Probably not.

Everton fans do not know their best team or players anymore – and nor did Koeman.

His tactics seemed to be unconvincing and lacking in conviction towards the end too, as he mixed and matched to try and find a winning formula.

The introduction of expensive new players has also come at the added cost of stunting the growth of immensely promising players such as Tom Davies and Ademola Lookman.

Everton owner Farhad Moshiri invested a lot of time and money luring Koeman from Southampton to Merseyside. He spent even more furnishing his chosen coach with a squad to match.

But now he will have to dig even deeper to pay him off and find a replacement worthy of the club’s motto.

Everton