When the first half ended in Real Madrid's Champions League meeting with Club Brugge on Tuesday night, Thibaut Courtois made his way off the pitch, the whistling loud in his ears, and everyone else's, too. Real were losing 2-0, and the goalkeeper who had conceded twice headed down the tunnel, into the dressing room and straight to the toilet, where he was sick.

Dizzy, disoriented and unable to carry on, he was replaced by Alphonse Areola as Real battled back to draw 2-2. Courtois' dad drove him home, and the next day, the keeper didn't join in training. "He had ... things," coach Zinedine Zidane said after the game, unable to offer a much better explanation.

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Sources close to the player have told ESPN FC that Courtois had felt unwell with gastroenteritis since lunchtime, while Real Madrid released a statement Friday denying reports the player suffered an anxiety attack.

Yet as far as anyone knew, there had been nothing wrong with Courtois before the game; as far as the fans knew, there was nothing wrong with him when the team came back out with Areola in goal instead. Which made what they did more than a little pointed. For a moment, the substitution seemed like a declaration of discontent from Zidane, maybe even a lasting declaration of intent, and it was one that many of them welcomed with applause.

If Zidane's decision wasn't a blunt statement, the supporters' response certainly was. They had whistled Courtois before, and at the Bernabeu there is no hiding place, still less when you're playing in goal -- exposed, all too aware of what is happening. As the final minutes of the first half ticked away, whenever the ball came to him, it was accompanied by long, loud whistles from a lot of people. "In the first half we can blame Courtois," Zidane said afterward. "But it is all of us, me above all."

Courtois, 27, probably shouldn't have been blamed at all, but he was. Flailing on the floor, he had looked a bit silly on the first goal, as a daft rebound off both of Emmanuel Dennis' legs wrongfooted him and dribbled past his hand into the net sufficiently slowly that some wondered if he could have even got up again to save it. For the second, Dennis had stumbled, almost falling, but had managed to lift it over the goalkeeper and into the net anyway. Maybe Courtois had started to go down too soon, and maybe he did look a little daft again. Zidane's assessment? "Both goals were a bit of a joke."

Neither goal was truly Courtois' fault; Sergio Ramos and Luka Modric were more culpable. However, he was the one in the photo: the beaten man, the breached last line of defence unable to defend the team. Which left him in the line of fire. He felt it. How could he not? The Bernabeu can be relentless and unforgiving, judgmental and cruel, even to the best of players.

Having rotated both Courtois and Keylor Navas in the final, empty months of last season, Zidane had been clear: "One thing is for sure: Next season there will be no debate in goal, I'm clear about that." But the debate about the Belgium international is now more alive than ever.

Navas had insisted that he wanted to stay and fight for his place this season, but eventually he embraced the inevitable and made a move to PSG -- with Areola going the other way on loan as backup. By then, Courtois had commented that it was clear who the No. 1 was and, while true, that didn't sit well. It also increased the pressure to prove that he was a worthy winner. Some supporters doubted that and were reluctant to entertain the idea.

Many felt Navas, a three-time European champion, didn't deserve to be asked to depart. And to be asked to depart again -- he had been literally waiting at the airport only for the deal to sign David De Gea from Manchester United in 2015 to collapse at the last minute.

Then the club had tried to sign Kepa to replace him, before Zidane blocked the move. When they eventually signed Courtois, Navas held on for a year, too. The fans admired the way he refused to take a hint, how he fought for his place, and how he saved them on multiple occasions with his performances. When he left this summer, there was no outright rejection of Courtois, but nor was there much warmth. The Belgian was good, but good is not always good enough, and the whole thing didn't feel quite right somehow.

That feeling continued on Tuesday night when Areola came on and immediately saved the team as Dennis ran clean through again. One of those polls beloved of the sports papers -- flawed, volatile, easily manipulated, it must be admitted -- showed that of over 100,000 AS readers, more than 80% thought that Areola should have started the game. Already.

On Thursday, the same paper's front page ran the headline: "This is not Courtois." His figures, they underlined, are far worse than they have ever been anywhere else. He's conceding 1.35 goals per game, but with Atletico, Chelsea and Belgium it didn't get over 1.0.

Those stats say as much, or more, about his defence, about the entire team, as they do about him. But it was a figure to damn him with. And it just wasn't very good. Not bad, exactly, just not that good. It showed that Courtois is not a miracle-worker, not a saviour, not a hero; just a goalkeeper, who picks the ball out of his net too often. He was supposed to be better than this. At Real Madrid, everyone is supposed to be better than this.

It is not like he has made many mistakes -- in fact it is a struggle to think of any at all -- but the problem for many is that they struggle to think of any saves. The saves he did make -- it was overlooked against Brugge that he made an important stop in the first half, or his sharp dive which prevented Koke scoring in the derby, or how he stopped Levante getting a last-minute draw at the Bernabeu -- passed by almost as if they weren't there.

He was, as one radio presenter put it, "invisible." He just didn't save anything. Where were the miracles? When was he going to rescue them? He was a bit ... well ... normal. At a club where that's not enough: Madrid are supposed to have the best in the world, and he wasn't. All those doubts reached him; how could he not have doubts of his own?

Courtois suffered when held up against his competitors, too. When was he going to do what Jan Oblak did for Atletico Madrid, or what Marc-Andre ter Stegen did for Barcelona? At the weekend, Ter Stegen had even provided an assist; Oblak had stopped Madrid. A superb save, the touchline reporter said to him. "Basic," the Slovenian replied. But if that's so basic, why don't we see it from our goalkeeper, Madrid fans wondered ...

In midweek, it happened again -- in Moscow, Barcelona and in Madrid. Courtois didn't start the fire, but he didn't put it out, either, and the whistles followed. Oblak saved Atletico and Ter Stegen saved Barcelona; Courtois didn't save Madrid.