Almost four years to the day since Ronald Koeman was sacked by Everton, the Dutchman was relieved of his duties once more.

On the day he left Goodison Park, it's doubtful anyone could really have predicted the next club side he would join.

Barcelona ignored the warning signs from their former player's stint on Merseyside and instead chose to focus on the respectable job he'd conducted in international football shortly after his Everton exit.

Koeman took over the Dutch national side and was progressing well until Barca came calling, and you don't ignore an opportunity such as that.

And so that left Evertonians in a very strange position last weekend watching El Clasico with two former Blues managers in each dugout - who left the club in different circumstances, granted.

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While Carlo Ancelotti has only just re-taken the reins at Real Madrid and, at the time of writing, has them sat atop the La Liga table just barely - Koeman has had anything but a comfortable ride.

Just in the last few months he's had to deal with the exit of Lionel Messi, a hugely restrictive transfer strategy and things falling apart on the pitch.

He is, however, a manager who failed to really connect with Everton fans during his time at the club - so sympathy around here will be fleeting, if at all apparent.

A penny for Oumar Niasse's thoughts in particular at this juncture...

But, rather confusingly to those of a Blue persuasion, it could all be set to happen again.

One of the favourites to take over at the Camp Nou, aside from club legend Xavi, is current Belgium manager Roberto Martinez.

His last club job was...of course, Everton.

It must be said that Xavi is seemingly the front-runner at this point, with many Spanish publications claiming the Al Sadd manager will be confirmed in the coming days.

But to even see Martinez's name linked brings up a lot of questions among Evertonians.

He's another who has managed to rebuild his reputation by heading into international football, taking over what has proven to be a golden generation of Belgian footballers.

Five years after leaving the Blues, however, rumours have been picking up around the Spaniard potentially moving to numerous clubs in recent weeks and month.

Right now, however, it must seem like Everton operate in a different universe to these giant Spanish clubs.

Take Koeman and Martinez, for instance. Both of their times of Goodison Park had spells in which their squad were playing some nice, effective football.

The latter's first season in charge of the Blues in particular was an excellent opening to his tenure. Taking over from David Moyes, he married defensive solidity with free-flowing attacking football in a way not seen for a generation at the club.

A record Premier League points haul from that campaign was commendable of course, but no silverware followed.

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The next two campaigns continued a downward spiral of managerial mishaps, including particularly a 3-2 defeat at home to West Ham which many would care to forget.

Martinez's spell in charge ended with protests at Goodison, with eventually a 3-0 humbling away to Sam Allardyce's Sunderland providing the final nail in the coffin.

That remains his last game in club management. A lot of time has passed since then, but being linked to a job as prestigious as the Barcelona one is still rather baffling.

For Koeman it was a little different, as he obviously has been a legend as a player with the Catalan giants in the past.

In fact, after his strong spell in charge at Goodison towards the end of the 2016/17 campaign, there was at one stage talk of potentially Barcelona swooping in for the Dutchman while he was still in charge at Everton.

Of course that didn't happen - and the less said about the first months of the following campaign, the better.

Before taking over at Barca in August 2020, Koeman's last match in club football was a dreadful 5-2 defeat at home to Arsenal which convinced Farhad Moshiri that he'd seen enough of his second permanent manager since making his investment.

Those warning signs didn't stop Barcelona appointing the Dutchman, however. He was dealt a bad hand at his former club, admittedly, but it's now hard to argue the Spanish giants shouldn't have thought twice on their decision.

This trend even comes up to the most recent summer, with Ancelotti's departure to re-join Real Madrid after what ended up being a largely indifferent spell at Goodison Park.

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Granted he slightly improved things in terms of points total in the Premier League, but only achieved a tenth-place finish after playing some frankly tedious football at stages.

The sheer clout that he carries, however, meant all that was forgotten when he made his return to the Bernabeu, however.

It isn't always the bright lights of La Liga for Everton's former managers, however.

Objectively the club's best manager since the turn of the century, David Moyes, is still rebuilding his reputation after taking over at Manchester United directly after his Goodison Park exit.

Now he's being lauded as the talented boss that he is once more, guiding West Ham very nicely into direct competition with Everton this season.

And, for Marco Silva, it was the Championship which was next on the horizon - although he may well be back in the top division again soon if he can get Fulham promoted.

Just this weekend, though, two of Everton's less-than-impressive former managers were in charge of each side in El Clasico.

You can forgive Blues for thinking they're in some sort of alternate dimension at times.