MADRID — The noise rose and swelled with every second that ticked, changing timbre and tone as it did so. It started with whistles, desperate and urgent, only to turn into something closer to a roar, formless and elemental, filled with angst and anticipation, as if the sound itself could ward off any more suffering.

By the time the final whistle blew, it was so loud that it seemed to be bubbling up from the ground or rumbling down from the sky. Somehow, though, that proved to be the prelude: The release was still to come, as Real Madrid’s and Chelsea’s players collapsed to the turf, the victors on the day defeated and the beaten triumphant over two legs, and the Bernabeu crackled and shook.

This is not the first time a Champions League game has ended like this, of course: The spectacular comeback and the breathtaking twist now rank as this competition’s calling card, a feature so regular that it is remarkable, in a way, that every time it happens it somehow retains its capacity to surprise.

It is not even like it is a rarity here. The sight of Real Madrid’s players, spread-eagle on the field in a state of pure, blissful exhaustion, having somehow turned certain defeat into a triumph actually happens with alarming frequency. It happened just a month ago or so, against Paris St.-Germain, for a start.

This is just what the Champions League does: produce evenings in which Villarreal, a team bobbing just above mid-table in Spain, can knock out Bayern Munich and still find itself overshadowed. It is just what Real Madrid does: flirts with disappointment, toys with disaster, and then flicks a switch and emerges victorious.

Even by those standards, though, Real Madrid’s draining, stirring, thrilling defeat of Chelsea — on aggregate (5-4), if not on the evening itself (a 3-2 loss) — managed to be more draining, more stirring, more thrilling than most.

There was not just one comeback, after all, but two, stitched together in the same marathon game: Chelsea overcame the two-goal lead Real Madrid had established in London last week, seemingly booking its place in the semifinals in the process, and then Real Madrid, beaten and cowed, rose from the ashes to snatch it away.

Everything turned on a single pass. For 80 minutes, Real’s fans had done nothing but suffer. They had arrived at the Bernabeu in high spirits, drifting up the Paseo de la Castellana filled with absolute confidence that Carlo Ancelotti’s team could get the job done. It is Real Madrid in the Champions League, after all. That is just how these things work.

It lasted all of 15 minutes, pierced in a flash by Mason Mount’s opening goal. The Bernabeu became unsettled, uneasy. Real Madrid seemed to freeze, as if arguably the most experienced, most grizzled team in Europe was not quite sure what the protocol was in this situation. Chelsea smelled blood.

Just after halftime, Chelsea’s Antonio Rüdiger scored — a simple goal, a header from a corner, as if all of this is quite easy — and the tie was level. An oppressive, fretful silence descended, the sound of 61,000 people waking up and remembering that, oh yes, this Real Madrid team is quite old now, isn’t it, and it’s been through a lot, and it’s in need of a refresh.

There was a brief flicker of hope when Marcos Alonso’s goal was ruled out for the slightest of handballs, but it proved illusory. A few minutes later, Timo Werner skated and skidded around the edge of the six-yard box and bundled the ball over the line. The jeers rained down, then, just for a moment. A few people headed to the exits. A few people always head to the exits. At this stage, everyone really should know better.

That was the mood, then, when Luka Modric got the ball, just inside Chelsea’s half, with 10 minutes to play. There was, to the naked and untrained eye, no option ahead of him; just Rodrygo, the young Brazilian wing, racing off on the other side of the field, dutifully tracked by a defender. Modric had no choice but to turn back, to change the angle of attack, to build again.

Or, it turned out, he could sweep a ball with the outside of his right foot just beyond the Chelsea defense and straight onto Rodrygo’s boot, inside the area, timed perfectly for him to steer a shot past Edouard Mendy without breaking stride. The pass did not exist. Modric found it anyway, and in doing so, Real Madrid found its belief.

That goal took the game to extra time, giving the home team, the impending Spanish champion, a reprieve. Real Madrid does not waste those.

Karim Benzema, scorer of all three of his team’s goals in the first leg, headed Real Madrid into the lead on aggregate with 96 minutes gone. By that stage, all sense of order had fractured, all thought of planning or reason or strategy cast to the winds.

Chelsea threw all of its players forward. Real Madrid’s substitute left back, Marcelo, ended up playing as a forward, for reasons that even he did not really understand. There were frights: a shot from Jorginho, a header from Kai Havertz. The whole evening, the whole campaign, seemed to hang by a thread.

All the while, the noise was building, yearning at first and then impatient and finally righteous and demanding. It became a place and a crowd crying to be put out of their misery. Nobody heard the whistle. Nobody could hear the whistle.

They knew it was over only when they saw the players on the turf, all the breath drawn from their bodies, their legs suddenly buckling, a conclusion at once impossible and inevitable. They should be used to this by now, really. This is how it always ends, at Real Madrid, after all. It just does not always end like this.