Cristiano Ronaldo's goal was his 15th in this season's Champions League

In a week where football has been at its chaotic best, Real Madrid and Juventus found a way to top it all.

The Champions League quarter-finals served up improbable comebacks, stunning strikes and pure emotion but it was at Real's fabled home the Bernabeu where perhaps the most exhilarating story of the competition's knockout stages unfolded.

No-one gave Juventus a chance. After all, no team in Champions League history has lost 3-0 at home in the first leg and gone on to wipe out the deficit in the away match.

But that's exactly what the Italian side did, until Cristiano Ronaldo stole the show late on.

Here's how an enthralling Champions League tie unfolded:

2nd minute: Juventus need an early goal and they get it as Mario Mandzukic heads home.

37th minute: Unbelievable! Mandzukic does it again as he rises to nod in a cross. Juventus are now just one goal behind on aggregate.

60th minute: They've done it! Somehow Juventus are level. Keylor Navas flaps at a cross and Blaise Matuidi is there to bundle the loose ball in. The tie is all-square with 30 minutes remaining.

93rd minute: Drama right at the end. Medhi Benatia's push on Lucas Vazquez is adjudged to be a foul and referee Michael Oliver points to the spot. Juventus goalkeeper Gianluigi Buffon is incensed by the decision and is sent off for dissent.

97th minute: With former Arsenal goalkeeper Wojciech Szczesny now in goal, Ronaldo steps to up to slam home the penalty and send Real into the last four with a 4-3 aggregate win.

Cristiano Ronaldo celebrated the decisive goal in some fashion

'Nerves of steel' - how Twitter reacted

Ronaldo coolness fails to mask Real's frailties

Spanish football writer Andy West:

When Michael Oliver pointed to the penalty spot in the 93rd minute, amid the bedlam of the Bernabeu - with Juventus players losing their heads, both sets of fans losing their minds and Real Madrid players barely able to watch - one man kept his cool: Cristiano Ronaldo.

Is there any other player in the history of football you would want to take that penalty? Despite the enormity of the moment, despite the heavy burden of pressure on his broad shoulders, despite the interminably long delay between the penalty being awarded and being taken, Ronaldo was unfazed.

He waited, steadied himself, stepped up, struck the ball with decisive intent… and watched it fly into the top right corner. Unstoppable. The perfect penalty.

Ronaldo's tie-winner sparked scenes of pandemonium inside the Bernabeu as Real fans celebrated a progression which they initially took for granted but which had then looked unlikely.

But in the long run it does nothing to mask the frailties of Zinedine Zidane's team.

It was a brilliant spectacle but still plenty for Real Madrid boss Zinedine Zidane to ponder, says Spanish football writer Andy West

True, they have kept alive their chances of winning the Champions League for a third consecutive season, but the manner of this 'triumph' could not have been less convincing and their narrow escape leaves more questions for Zidane than answers.

Several individuals will come under scrutiny, starting with Zidane himself who would almost certainly have been removed from his position in the near future if Juve had won the tie. Ronaldo's penalty has given Zidane a reprieve, for now, but there's still a great deal of uncertainty over his future.

The same applies to Gareth Bale, who has dropped down the pecking order over the last few months and suffered the humiliation of a half-time substitution following an anonymous opening 45 minutes. The prospects of the Welshman returning to the Premier League have never been greater.

Goalkeeper Keylor Navas is also in trouble. The Costa Rica international has always been skating on thin ice ever since taking over from Iker Casillas between the posts three years ago, and a terrible error for Juve's third goal will heighten the speculation that Thibaut Courtois or David de Gea will displace him this summer.

Ronaldo's penalty also provided a let-off for La Liga's reputation. Spanish football has dominated Europe's top honours in the past few years, but with Atletico Madrid knocked out in the group stage and Barcelona and Sevilla exiting in the quarter-finals, defeat for Real would have led to the first semi-finals without any Spanish representatives since 2007.

That scenario might have been averted, but on Wednesday's showing Real looked anything but European champions. If we've learned one thing from history, though, it's this: in the Champions League, never write off Real Madrid.

'They thought it was a joke to believe in a comeback'

BBC Radio 5 live Euro Leagues Football Show host Mina Rzouki:

After the first legs, the Italian press were super harsh on Calcio [Italian football]. They were mourning it, they were saying that they had become an inaccessible planet. Fabio Capello agreed with all the criticism. One of the press said it was a joke to even believe in a comeback for Roma against Barcelona.

It was like 'wait, hold on a second...' Juventus knocked out Barcelona last year and are the only team to knock out Real Madrid in the last four years, and Roma really proved themselves against Atletico Madrid earlier in this year's competition. I didn't understand why there was all this hubbub about Calcio being over.

On this occasion I thought it was a case of 'we will take your Spanish technique and raise you our Italian tactics'. That is what should have won out tonight, but for this madness at the end.

I can see why it was a penalty but unless I've missed something, how can you send Buffon off like that? It is going to be an emotional moment for any player.

Having watched this week's Champions League matches I thought Man City were hard done by, Roma were hard done by in the first leg with Barca.

A lot of people, including myself, were very critical of Buffon after the first leg. He was in awe of Real Madrid and Ronaldo. He waited patiently to go and hug the striker at the end of the game. Smiles all round. Where was the disgust and disappointment of conceding three at home? This time he proved what it is to have a competitive mentality. He went crazy. I guess this may be how he ends his Champions League career.

Gianluigi Buffon was sent off in the Champions League for the first time (he has played 117 games in the tournament)

'Juventus had earned the extra half hour of theatre'

The Independent's sports editor Ed Malyon on BBC Radio 5 live:

Extraordinary. What an ending. I thought the penalty was a little soft. Chiellini goes for the ball and gets a bit of the man. Lucas Vazquez is already going down. In a big game you've got to be sure, and I'm not sure you can be that sure [about it being a penalty].

The way Real played, they would not have scored in open play so they needed a penalty, and amazingly an English ref gave it to them.

It is a shame that if this is Buffon's last ever Champions League game, he is going to go out on a sour note. A very sour note.

I think there is the feeling that Juventus had earned the extra half hour of theatre at the end of the game. To go to the Bernabeu and win 3-0 is quite a feat and for it to go down to that final moment is crazy. It is almost like an NFL game where it is set up for this one last play that everyone has time to digest.