TODAY will offer the clearest indication yet of whether we have a realistic race on our hands or whether we really will go down the rabbit hole and witness Leicester City pulling off what may well be the most improbable sustained upset in the history of sport. And yes, we are talking “sustained upset”, as in, sustained over nine months. You may be able to find longer long shots who did it in a knockout competition or on a single day. To do it over 38 games and nine months is Twilight Zone stuff.

The gap is seven points. Tottenham host Manchester United, while Leicester City are away to Sunderland, desperately scrapping to avoid relegation. Simply put, if the margin is still seven points this evening, it will take something divine or Herculean for Tottenham to be crowned champions. But if they beat Manchester United and Leicester fail to win, the race rolls on for another weekend. Five points is hugely difficult, but doable. Seven points in five games requires that guy with a beard, sandals and a knack for feeding hundreds with just a couple of loaves of bread and a few fish.

Yet whatever happens in the next five weeks, these two clubs will have made history. A second-place finish for Spurs would be their highest in 38 years; a third-place their best in 16 and – should they win it – it would be the first time since 1961 (before Daniel Levy was born).

As for Leicester, it is already the greatest season of their 135-year history. Finishing second would represent their best finish since 1929, the year the stock market crashed.

The question then becomes what beckons next year. To what degree can they build on that success?

Tottenham are, of course, the bigger, wealthier club. And they are the ones building a 61,000-seat cash-cow of a stadium, set to open in 2018. (Right now, it goes by the decidedly unsexy name of Northumberland Development Project, but no doubt, that will change.) None of their starters are older than 29 and all but four – Toby Alderweireld, Jan Vertonghen, Mousa Dembele and Hugo Lloris – are 25 or younger. Plus, they have one of the most prolific academies around. Danny Rose, Ryan Mason, Josh Onomah, Tom Carroll and, of course, Harry Kane have all seen significant playing time and are home grown.

That bodes very well for the club. As does the fact that they have been run at a profit for years (and the margins will only improve once the new stadium is open and the new TV deal kicks in) suggesting they could, if they so chose (and that has been an issue in the past), pursue name-brand stars in the future.

The wild card seems to be the manager, Mauricio Pochettino. The Argentine’s success has prompted speculation that he could be in the cross-hairs of the usual superclubs. That much is inevitable and yet a quick gander at the landscape suggests he has few potential destinations in the immediate future.

There is Manchester United, of course, but even if Louis van Gaal sticks around or the Dutchman goes and Jose Mourinho does not replace him, it’s by no means clear that having worked so hard to reach the Champions League, he would pack it in for a club that is by no means assured the European big stage.

The other English big boys look set for the next few seasons (Arsenal may be the exception but we can rule them out for obvious reasons; Pochettino is no Sol Campbell).

He played most of his football in Spain, of course, but Barcelona is likely a no-go for the same reasons as Arsenal – he played for, and managed, Espanyol. Which leaves Real Madrid, though you get the sense that Florentino Perez only goes for guys he has seen in the Champ-ions League or who are Zidanesque in reputation. All of which points to the fact that Spurs can come back stronger next season and beyond.

As for Leicester, it’s a somewhat different issue. When they returned to the top flight, chairman Vichai Srivaddhanaprabha said he planned for a top-five finish in three years. (Why top five when everyone else thinks in terms of the top four? Who knows?) Few noticed, possibly because it seemed absurd. Yet the funds to invest, not just in players but in infrastructure too, are there.

Still, it is a much bigger ask and not just because Leicester isn’t London and the fan base is far smaller. The good news is that, other than N’Golo Kante and Riyad Mahrez, who are both 25, there aren’t any top-shelf saleable assets in the prime of their careers who will be looking for an upgrade. The bad news is that those two are pretty darn integral to the club’s success.

What’s more, in terms of age, they are the opposite to Spurs. Kante and Mahrez are the only starters younger than 26 and more than half the starting XI are 29 or older. That suggests that most of these players will need to be replaced in the coming years. Finding replacements of equal (or greater) quality, even with pockets brimming with new-found revenue, won’t be easy.

POLARISATION? What polarisation? The Champions League quarter-final first legs were a slap in the face to conventional wisdom with the fracture between rich and poor, super-clubs and once-great-now-comparatively-pedestrian sides may be not quite as extreme as we thought.

Atletico Madrid escaped from the Camp Nou with a 2-1 defeat, despite playing most of the game with 10 men. Bayern could only manage a 1-0 home win over Benfica. And Real Madrid, of course, fell at Wolfsburg, 2-0.

As for Manchester City, they are hardly minnows, though momentum (and prognosticators) were with Paris St Germain, yet they too upset the apple cart with a 2-2 draw in France.

The upshot is that all four quarter-finals hang very much in the balance. And we may well see multiple juggernauts ejected from the Champions League party at this stage. If that happens, it won’t represent a levelling of the field. It will just mean that the one-percenters have squandered their privilege.