What a brutal way for Atletico Madrid to celebrate their birthday. Founded on April 26, 1903, they played exactly like they were 118 years old -- full of tired mistakes, forgetful 'senior' moments and bewildered expressions in a 2-1 defeat at Athletic Bilbao on Sunday night.

It's a result which gives us the tightest, most exciting top-four race since La Liga became a 20-team league a quarter of a century ago.

In case you've consumed the results, but not glanced at the top of the title race, we have stumbling Atleti on 73 points, reigning champions Real Madrid with 71, sudden favourites Barcelona (having played one game fewer) on 71 (but trailing behind Madrid because of the head-to-head record of having lost both Clasicos), and the ultra dark-horse coming up fast on the rails: Sevilla FC on 70 points.

The positive news for Atleti -- which my goodness they'll need -- is that only three times since 1997, when the 38-match season began because La Liga shrunk from 22 to 20 clubs, has the top team lost that lead with five games to go and said a tearful "adios" to the title.

The first time anyone who topped La Liga after 33 matches stumbled, fell flat on their face and then begged never to be reminded of the aberration was in 2002 when Real Madrid, coached by the Vicente Del Bosque, and featuring none other than Zinedine Zidane, led Rafa Benitez and Valencia in early April courtesy, only, of a superior goal difference.

But horrible defeats to Real Sociedad, Osasuna and Deportivo La Coruna sent Los Blancos into a tailspin which only steadied off when, having eventually finished third, they lifted the Champions League at Hampden against Bayer Leverkusen.

Not bad as consolation prizes go.

A year later came the second implosion. Poor old Deportivo La Coruna (remember them?) led Real Sociedad on their head-to-head records and third-placed Real Madrid by a point after that season's 33-game slog.

But by June 22 (yes, that REALLY was when La Liga's title used to be decided!) Del Bosque, Zidane and the stunning Ronaldo-Raul partnership had pipped La Real with Deportivo eventually languishing back in third.

And the only other time, at least until now, when a leader keeled over with the title a mere 450 minutes away, was when the wheels were about to come off Frank Rijkaard's Barcelona in 2007.

Leading Madrid by two points after Matchday 33, Barca, starring Xavi, Andres Iniesta, Lilian Thuram, Deco, Samuel Eto'o, Ronaldinho and Lionel Messi promptly flopped 1-1 at home to Real Betis conceding a last-minute goal to Brazilian winger Rafa Sobis in front of 78,000 infuriated Blaugrana fans at Camp Nou.

That was that.

They and Fabio Capello's Madrid matched results like-for-like right until the end of the dramatic last day meaning that, tied on 76 points, Los Blancos were champions thanks to a better head-to-head Clasico record that season.

The fact that such collapses so close to the line are rare, of course, gives no guarantee that we aren't about to see a fourth member of that excruciatingly embarrassing group -- the "Close But No Cigar gang."

Atleti, even if only just, still have their title fate in their own hands.

Should they win every one of their remaining ties they win the title. It's that simple.

The reason is because even though Ronald Koeman's relentless Messi-driven machine (they've won 46 of 51 points since late December) most probably beat Granada on Thursday at Camp Nou to go top by a point, there remains the massive weekend in early May when Madrid host Sevilla and Atleti travel to Barcelona.

If, somehow, Diego Simeone can waken his Rip Van Winkle team up, instil a bit of fight, get Luis Suarez sharp and scoring again then a win at Camp Nou isn't completely beyond them.

How much would the feisty Uruguayan enjoy paying Koeman back for that phone-call last summer when, on behalf of the now departed and disgraced Josep Maria Bartomeu, the Dutchman told Suarez that he was surplus to requirements? I think you know how much.

Los Rojiblancos haven't beaten Barcelona at Camp Nou since February 2006, but even a draw (something they've done in three of their last seven visits) might be sufficient if Koeman's team stumble in their slightly tougher run-in, especially at Mestalla next weekend.

But the teetering, tentative progress of Atleti, who've only won Spain's title twice since 1977, isn't the only remarkable facet of La Liga's 2020-21 season.

The spread of points between top, Atleti, and fourth, Sevilla is just three. In context that's amazing.

Not only is it significantly the tightest contest across any of Europe's major leagues (with a respectful nod to the four way punch-up at the top of Ligue 1 in France), it flies totally in the face of the last 24 years in Spain.

Thirteen times at this stage of the season the spread between first and fourth has been fifteen points or more. And if you want to think about the absolute extremes, when either Madrid or Barcelona were playing steamroller football, the gap between first and fourth has been (in 2012, 2011 and 2010) 35, 31 and 29 points, respectively.

At the time of writing if you drop 35 points from first-placed Atleti you'd arrive at 12th-placed Levante, who've won only once in their last nine and are nine points off the bottom three!

A truly remarkable turn of events compared to most of the seasons preceding this one.

Hardly an outright outsider given their two Champions League finals appearances, one league title and a Europa League win in the last seven years, Atleti look as though their knees are knocking together in either fear or exhaustion or both.

I guess many neutrals will be roaring on Sevilla. The Andalusian side are three points off top of La Liga, a place they'd normally need a crampons, ropes, a sherpa and oxygen to scale, and they've not won Spain's title since just after World War II.

But Julen Lopetegui's brilliantly constructed squad have won five straight matches and although they travel to face Real Madrid on May 9, they appear to be the freshest, least distracted team -- the challengers with the best momentum.

Which, of course, is where Spain's idiosyncratic (but likeable) head-to-head rule comes into play.

If two teams finish on the same points anywhere up and down La Liga's table they are separated on which of them has a better score aggregate against the other.

If they happen to be identical then the team with the better goal difference across the entire campaign wins.

As it stands, Atleti beat Barcelona 1-0 in their only match so far, and a win or draw at Camp Nou on May 8 would give them the definitive head-to-head advantage. Atleti lose the head-to-head with Madrid, but win it, by 2-1 on aggregate, against Sevilla.

Sevilla don't currently win the head-to-head with any of the rest of the top four but could change that at Madrid on May 9 if they win 2-0 (having lost 1-0 to Madrid at the Sanchez Pizjuan in December).

Barcelona lose the head-to-head with Madrid, win it against Sevilla and are balanced at 1-0 down against Atleti pending their big showdown in two matches time.

So, for those who've always complained when Madrid or Barcelona are so muscularly brilliant that the title race is between the two of them by April, it's time to sit back, savour what's happening but accept the fact that it takes tremors, stagnation and turmoil at Spain's two behemoth clubs for the others to get to within touching distance like it is right now.

It's countdown time. Atleti looking like they are on the edge of a nervous breakdown, Madrid looking like winning the Champions League is priority No. 1, Barcelona looking like strong favourites (for what, pound for pound, would be one of their biggest and most surprising title wins) and Sevilla undoubtedly the neutrals' favourites to stun Spain, shock the world and see whether La Liga's throne really is made to measure for them.