(CNN) -- Tuesday -- Barcelona.
It was supposed to be the end of an era, the end of a generation.
Had it not been for a post, then perhaps the world would be looking at a different future. Football is nothing but fickle.
The headline will be Barcelona's 4-0 annihilation of AC Milan, swatting aside the critics and doubters in the only way that this great team know how.
Had the ball deflected off the post and spun the other way, the chilling inquest into Barcelona's fall of grace would have already begun.
The biggest of games, the smallest of margins.
Trailing 2-0 from the first leg, Barca was in a supposed crisis, its crown as Europe's dominant force precariously balanced.
Consecutive defeats to arch rival Real Madrid in domestic competition and the anemic display at San Siro just three weeks ago had stoked the fires.
But on this occasion, it was not just at the Vatican where black smoke rose across Italian skies, but also in Milan, as its Champions League dream went up in flames.
It could have been a different story -- but history is written by the victors and Barcelona were victorious by a considerable distance.
Without coach Tito Vilanova, who is still undergoing cancer treatment, question marks had emerged about the ability of the club to make it through to its sixth consecutive quarterfinal.
And perhaps, but for a post and a roll of the ball, those questions would have been answered quite differently.
Maybe the opportunity fell to the wrong man. At just 18, M'Baye Niang cut an unlikely cast member for the role of hero.
Without a goal to his name since his move to Milan at the end of last season, it was he who was given the golden opportunity to bring Barca to its knees with just seven minutes of the opening period remaining.
Already trailing to Lionel Messi's fifth minute strike, Niang took advantage of an error by Javier Mascherano before gliding towards goal.
This was the moment that Milan had waited for and while Niang hit his effort hard and true, it crashed against the post and away to safety.
An away goal then would have given even Barcelona a mountain to climb with a minimum of four goals needed to progress.
Whether Barcelona's world would have crumbled had that ball nestled in the far corner will never be known, but had it done so, then Milan would have at least given itself a chance.
That Barca recorded four anyway will not help Niang sleep any better.
There is little room for "What if?" in sport however and Barcelona left little to chance as it went on to produce a mesmeric performance.
Only last week, a Japanese jeweler created a 25 kilogram solid $5.25 million gold statue of Messi's left foot, although the price may well rise following his latest exploits.
His early strike, a sumptuous effort following a delightful pass from Xavi, was his 57th in the Champions League, placing him second behind Raul in the all-time top scorers of Europe's elite competition.
His 58th came less than 100 seconds after Niang had threatened to send shockwaves throughout Europe.
This time, albeit with a suspicion of offside, Messi unleashed an unstoppable drive from 20-yards after Massimo Ambrosini had gift wrapped possession to the Barca man.
The halftime whistle brought some solace for Milan, but it only delayed the inevitable.
If there were any statisticians in the Milan dressing room then they may have known that Barcelona had won both of its previous games during a papal conclave.
But not even a prayer was going to help the Italian side out of this.
Just 10 minutes of the second period had elapsed when Kevin Constant's dreadful error allowed Xavi's pass to skip into the path of David Villa, who curled an exquisite effort into the far corner.
Milan threatened sporadically and a wonderful block from Jordi Alba denied Robinho as Barcelona began to look nervous for the first time in the contest.
But Alba soon laid any worries to rest, racing onto Alexis Sanchez's pass deep into stoppage time before slotting the ball past Abbiati.
For Roura, the result was a relief.
"If there was anyone not sure about Messi then this was the perfect response as he took charge of the game with two goals and showed again that he is an extraordinary player, out of this world," he told reporters.
"Before we weren't so poor and now we are not so great and I wouldn't describe ourselves as favorites for the competition.
"At any stage of the game until the final goal we could have gone out if we had conceded and I would have said the same that we played well and were composed."
Crisis? What crisis.
In the night's other game, Galatasaray booked its place in the last eight with a dramatic 3-2 win over Schalke in Germany to progress 4-3 on aggregate.
Following a 1-1 draw in the first leg, Schalke looked set to progress when Roman Neustadter prodded home from close-range.
But Galatasaray, boasting the likes of Didier Drogba and Wesley Sneijder, was soon level thanks to a stunning 25-yard drive from former Schalke player Hamit Altintop.
Burak Yilmaz then grabbed his eighth goal of the competition to put Galatasaray ahead and put himself top of the Champions League goalscoring charts.
Marco Hoger smashed an effort against the crossbar with 63 minutes gone before Michel Bastos leveled soon after.
But with Schalke pushing up for a winner, Umut Bulut raced through to score and seal his side's place in the quarterfinals for the first time in 12 years.
"We showed we deserve to be in the quarter-finals, but it was a close game and both teams had their chances," said Altintop.
"Perhaps we had a bit of luck at the end, but I'll take that.
"We responded well to fight back after conceding the early goal."