Buffon, the perennial Champions League fall guy, the Juventus veteran with three runners-up medals making his 117th and last appearance in the competition, is sent off by referee Michael Oliver for protesting against the awarding of a stoppage-time penalty. And Ronaldo, the man with four Champions League winners medals in his pocket, is given the chance to not only mark his 150th appearance with his 120th goal from the penalty spot but also to salvage a place in the semifinals for Real Madrid by extinguishing Juventus's sensational fight-back.

Buffon, who angrily confronted Oliver after he penalised Mehdi Benatia for a clumsy shove on Lucas Vazquez, was off the pitch and down the Bernabeu tunnel by the time Ronaldo guided his spot-kick beyond helpless substitute goalkeeper Wojciech Szczesny to make it 4-3 on aggregate to Real in the dying seconds.

It was brutal on Juventus, who had stunned the European champions by cancelling out the 3-0 first-leg lead built up by Real in Turin just eight days ago. Massimiliano Allegri's team had seemingly pulled it out of the fire with two goals from Mario Mandzukic and one from Blaise Matuidi to level the aggregate score. From there, Juve were looking strong enough to go the distance by winning the tie in extra time. But along came Ronaldo, the ultimate glory boy, to cast Buffon into retirement with his one last chance of Champions League glory snuffed out in the most dramatic and cruel circumstances.

It was pure theatre in the Bernabeu, a return to the old days of the bullrings in the Spanish capital, with Juventus -- and Buffon -- the victims.

Real coach Zinedine Zidane, watching from the touchline, was a witness to Buffon's final chapter just as the Italian goalkeeper was back in 2006, when Zidane was infamously sent off for head-butting Marco Matterazzi during the World Cup final in Berlin. That red card remains a stain on Zidane's glorious career and Buffon must now hope that his first Champions League sending-off does not become the first point of reference when the reflections begin on his illustrious career.

Whatever springs to mind for the goalkeeper, Ronaldo will not be far away. The Real forward plunged the dagger in this game with his penalty, but he also beat Buffon last week with the stunning overhead kick in Turin that is now being described as the best goal in Champions League history. Then there were the two goals in Cardiff last June, which formed part of Real's 4-1 win against Juventus in the final that denied Buffon that elusive winner's medal once again.

Yet this was not supposed to be a game that delivered such drama. With Real returning from Italy with a three-goal lead, an eighth successive Champions League semifinal appeared beyond doubt. It was surely just a case of turning up and getting the job done. Barcelona may have thrown away a three-goal lead against Italian opposition 24 hours earlier, when Lionel Messi & Co. were dumped out of the competition with a 3-0 defeat against Roma, but that was in Italy.

This was in the impregnable Bernabeu, and Juve should have had no chance. Yet the Italian champions were 2-0 up on the night by half-time thanks to Mandzukic's double and Real were awful.

Gareth Bale, making a rare start for Zidane's team, was substituted at the break due to his anonymous first-half display, one that may signal the beginning of the end for the Wales international in Madrid. But Bale was not alone in not being able to put one foot in front of the other for the Spanish giants. All of Zidane's players, Ronaldo included, produced their worst performance for months or maybe even years as Juventus won every challenge and created every chance.

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When Matuidi made it 3-0 and levelled the aggregate scores on the hour, the unthinkable had happened and Real's lead had been erased. It was looking like Ronaldo would miss out on the chance to win a third successive European Cup, while Buffon's impossible dream of winning his first was back on.

Yet the final act had still to be played and it was always going to involve Ronaldo. He always comes to the rescue for Real and, when Oliver pointed to the spot following Medhi Benatia's challenge, he had his chance. But Buffon lost his head, exploding with rage as he barged into Oliver, and the red card emerged.

Oliver could have sent off any one of five or six Juventus players following the melee that ensued, but Buffon was front and centre of it, so he paid the price. Ronaldo, having waited five minutes for calm to be restored before taking his penalty, displayed the cold-blooded instinct of a matador by converting from the spot.

He and Real live to fight another day, but Buffon must now count his regrets. He must also hope that Oliver's red card ultimately fades from the memory in a competition that has, in truth, done him few favours.