Thibaut Courtois isn't simply the world's No. 1 goalkeeper. In fact, his imperious form is such that he's easily among the top three or four footballers -- any position, any club. Were the Ballon d'Or Award moved to this week instead of December, Courtois would be mighty close to becoming the first keeper to win it since the legendary Lev Yashin in 1963.

And, hypothetically, were Courtois to be the key to Real Madrid somehow knocking Paris Saint-Germain out of the Champions League on Wednesday, after Los Blancos played excruciatingly badly in the 1-0 first-leg defeat, he'd be a shoo-in to succeed Yashin 58 years later.

Just picture the scene: the big Belgian who gave up the sport -- he was sick of it, aged 11, only to change his mind and abandon a potential volleyball career -- is about to become the only Real Madrid keeper (ever, in all likelihood) to face a Lionel Messi-Kylian Mbappe-Neymar trident at the Santiago Bernabeu. About to face a mercurial front line of all-time great strikers who have racked up 197 Champions League goals between them.

It also means he's about to face Messi, approaching an 11-year thorn in his flesh, for the 16th time.

The Argentine genius (and let's have no arguments about that description) has scored 26 goals against Madrid and the last time he heard the Champions League anthem at the Bernabeu (2011), it inspired him so much that not only did he score twice, he tucked away one of the very best of his 759 goals so far.

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Courtois' first encounter with Messi will be 11 years ago this September. It's seared in his mind.

It was his eighth match for Atletico Madrid on loan from Chelsea, at age 19, and he was flying. He'd conceded just one goal for Los Rojiblancos in the previous seven, but was sent home with a 5-0 hammering and fell victim to a Messi hat-trick.

"Strangely, despite the 5-0 result, that day was like a dream come true for me," Courtois said afterwards. "Playing at Camp Nou was of the things I used to fantasise about as a kid. When I went back to the dressing room after the game my teammates said to me, 'Welcome to Spain!' Then I was walking through the catacombs in the stadium, and there was a guy coming towards me. I didn't recognise him until he spoke to me. It was Pep Guardiola, and he said 'you're playing very well. Keep it up!'

"Messi also congratulated me after the match. His three goals were unstoppable, but I managed to make a couple of saves I was proud of. The thing with Messi is that he looks like he's doing absolutely nothing while the rest of the team kick the ball around. Then, all of a sudden, he can burst into action and deal the fatal blow."

It was a tough lesson that contrasts, strongly, with recent Messi vs. Courtois battles.

Messi has nine goals from 19 times facing Courtois. The trouble is that those nine goals all came in their first seven years of their rivalry: Barcelona or Argentina vs. Atletico, Chelsea or Belgium. Messi has never scored against Madrid when Courtois has been in goal -- a record extended at the Parc des Princes last month when he saved his penalty, part of a display that prevented a 1-0 defeat from turning into a thrashing.

If PSG had won by four or five, nobody could really have complained. With notable support from Eder Militao, Courtois utterly excelled, just like he has been doing all season: he has 16 clean sheets and there have been countless matches where, were it not for his brilliant one-on-one saves, Madrid would have hemorrhaged points.

Keeping the tie alive in Paris won't mean anything unless Courtois matches, or improves, that brilliance this week. But he's ready.

Courtois explained his preparation: "We watch video footage of our opponents before every game. We need to analyse their style and identify anywhere they could be dangerous: free kicks, penalties, etc. We watch hours and hours of footage and then discuss it.

"It's the discussion that is the really crucial bit. It helps me work out my own perspective on the game. When you pause the video, it's so easy to see every detail of the pass, but obviously it's totally different you're on the pitch. When you see it on the screen the space on the pitch looks enormous, but it's much tighter in reality.

"Prematch, our goalkeeping coach, Luis Llopis, prepares a dossier for me showing the opposition's last five or six penalties, and a video showing the goals and penalties of seven or eight different players. I'll have a look, tell him what I think and he'll give me his thoughts. We almost always agree. It's an important part of the process that makes a huge difference when it comes to saving penalties in the match. Recently, it's really paid off for me."

There will be a couple of side notes on Wednesday, too. Courtois won't give them much head space on purpose, but they'll be there.

Courtois has only faced Mbappe three times, but the past two saw his potential Real Madrid teammate next season score twice and collect an assist. Three weeks ago, Mbappe's 90th-minute winner in the first leg was painful enough, but it was not yet definitive. A much more bitter memory will be of Belgium sitting 2-0 up on world champions France in Turin last November during the Nations League semifinal only to lose 3-2, partly thanks to Mbappe's penalty and his assist for Karim Benzema. (It's unclear, as of this writing, if Mbappe will play after picking up an injury during training on Monday.)

This week is a good time for Courtois to staunch the flow -- if he can. If Madrid are to progress, at least. Meanwhile, goalkeeper Keylor Navas will be on the PSG bench unless Mauricio Pochettino has a radical change of tactics and drops Gianluigi Donnarumma. Former Real Madrid defender Sergio Ramos will be amongst the travelling Parisian party, but not dressed for action given his recent injury struggles.

Each man represents a little victory on Courtois' path to world pre-eminence.

When he signed for Los Blancos -- "A dream I'd always had... I had a Madrid pennant up on my wall as a kid and Iker Casillas was my example of what a keeper should be... I watched so, so many videos of his games!" -- he had to work to displace the Costa Rican keeper who'd just won three straight Champions League finals. Navas wasn't for budging, and Ramos didn't trust Courtois to consistently rescue him after one of his infamous upfield excursions as much as he trusted the phenomenally agile and cold-blooded Navas.

It wasn't an atmosphere conducive to a former Atletico Madrid player, signed on the direct request of the president rather than the coach, flourishing. But typically, Courtois did flourish. He saw off Navas, won Ramos over and reached this nirvana of form and status -- he's the dressing room leader now that Ramos has departed -- while having worked significantly on his ability to play out from the back and field the ball, at his feet, in pressure situations.

Courtois recently told Madrid television: "I reckon I'm in the best form of my career. For the past two or three years, my level has been good and I've made the difference for our team. Last season was one of my best ever, but we didn't win any trophies so people tend to forget. Except our fans and the people at the club, of course.

"My No. 1 task is to prevent goals, but the keeper's also important when we're bringing the ball out from the back. It's an aspect of our game we need to improve, and I'm working hard to support the team in that area. Most of all the coach needs me to make the difficult saves, whenever the team is struggling."

Courtois won't have either full-back Ferland Mendy or midfielder Casemiro (both are suspended) in front of him this week, and he'll be facing a PSG side equipped to win -- either via moments of individual brilliance, or on the break as Madrid try to answer the baying call of a fanatical, hungry Santiago Bernabeu roaring them on to another famous remontada (comeback) win.

Someone else has to score the goals, while Ancelotti has to pick the right XI and the right strategy. The players in white shirts need to match the physical and mental velocity of hugely dangerous opponents, too, but unless Courtois produces one of his signature nights, playing like a Ballon d'Or candidate, then Madrid are going out.

The truth is: he's good enough to do just that, and to give Los Blancos a chance to beat the odds. What more can you ask for?