If the question is "what is wrong at Tottenham Hotspur?" then the answer is certainly "Mauricio Pochettino." Although as with most things in life, it is not quite as simple as that.

The Argentine, in his sixth season at Spurs, is facing something of a crossroads. His position at the club has long seemed impermanent but now his authority is being challenged by twitter trolls, message board heroes and the media alike. Last years Champions League Final seems a long time ago even if Pochettino seems unable to utter a sentence without mentioning it. There are some who say the manager should be fired. But how do you fire a guy who has just delivered the biggest game in the clubs history, even if he has also just overseen the biggest home defeat in 137-years of Tottenham Hotspur? Others predict, or have been predicting for a while, that Pochettino is just biding his time until one of the really big jobs becomes available.

Pochettino himself said he might have walked away if Spurs had won the European Cup and the feeling now exists that heading for the exit could have been better for everyone. You see, five years is a long time in football nowadays. Take away Alex Ferguson and Arsene Wenger and try to list the managers that have lasted five years at a single club in the Premier League era. How are you getting on? Anything yet? Everton fans will have come up with David Moyes, Liverpool fans will remember Rafa Benitez; but who would have thought Joe Kinnear at Wimbledon or Jim Smith at Derby would make the top ten? Pochettino is already equal ninth on the longevity list, it is just not the done thing these days. Closer examination of the two behemoths of Premier League management further complicates the picture. Wenger, who won his final league title eight years into his twenty-two-year reign, spent his final decade at Arsenal under constant scrutiny and criticism. Ferguson, of course, was a different animal and in possession of a skill that no other manager in British football history has had. Ferguson reinvented his Manchester United team multiple times, he jettisoned star players and rebooted his team so regularly that one can picture a young(ish) George R.R. Martin watching with interest, fingers hovering over the typewriter.

(OK, I know. I know football existed long before the Premier League but things were different then and it took long enough to compile this list. I also know that some of the above managed their clubs for longer but this is about the Premier League and so must be a continuous stint to be included.)
<grammarly-extension class="_1KJtL" style="position: absolute; top: 0px; left: 0px; pointer-events: none; z-index: 1;">
 
</grammarly-extension>

In the modern era of football, the great coaches know when to end one chapter and start penning another. Pep Guardiola certainly knows it. He left Barcelona before his reputation was damaged, signed and honoured a three year deal at Bayern Munich and one suspects he will wave goodbye to Manchester City within a couple of years or as soon as the Champions League trophy is on display at the Etihad. José Mourinho knows it too, even if he does have his very own abrasive way of going about things. The Portuguese arrives at a club interested only in winning trophies. Making friends, winning hearts and minds, building a legacy, these are not things with which José concerns himself. Whilst this approach makes him ultimately unpopular and an estate agents dream, his collection of silverware is the envy of nearly every other manager in the modern era.

All of which brings us back around to Mauricio Pochettino and Tottenham Hotspur. Does he really want to stay at Spurs for the long haul? Is he really invested in this project or do his eyes moisten at the thought of leading out teams at Old Trafford or the Bernabeu? If he wants to stay then reinvention needs to happen sooner rather than later, you cannot build sustainable success if the spine of your team wishes it were elsewhere. A drastic Fergusonesque shake-up is required at Spurs if Pochettino intends to remain and build a true legacy. If he doesn't then perhaps it is time to put a full stop on his time in North London before things turn nasty.

Pochettino has already outlasted all but nine of his Premier League counterparts and will move ahead of Jim Smith when today's match against Brighton gets underway. Spurs might well win at the Amex and they might well beat Watford in a fortnight, but such short term successes will not and should not gloss over the big questions facing everyone at the club.