Former Manchester United keeper Edwin van der Sar believes that Courtois must improve his coaching ability if he is going to live up to his potential of becoming the world's greatest goalkeeper.
The Belgian rejoined his parent club, Chelsea, this summer after three very successful season-long loans at Spanish side Atletico Madrid. He has fast become Jose Mourinho's number one choice between the sticks, resigning experienced veteran Petr Cech to a place on the substitutes bench.
While some already regard the 22-year-old as the finest shotstopper in Europe, retired Dutch legend Van der Sar believes there are areas of his game that still need improving upon.
He told The Telegraph: "Is he already the best in the world, like some say in Belgium? They say that too easily nowadays, don't you think? In my period, the Dutch also thought I was the best in the world.
"The most important thing is that Courtois keeps on performing on a consistent, high level. He's on the right track. His career is going upwards, but he has some aspects in which he still can make progress. His coaching for instance.
"His composure is excellent, but there's a difference between shouting and coaching. Shouting is pretending, coaching is all about helping your team."
Many in the game have likened the Chelsea youngster to Van der Sar, which is little surprise considering Courtois openly admitted that the Dutch legend is his all-time hero.
Van der Sar, 43, added that he understand where the comparisons come from and that Courtois massive progress already is of no surprise to him.
"We are both tall and don't have wide shoulders, either. On top, our actions and charisma are quite similar too. So yes, I see why they compare us.
"His progress hasn't surprised me. He has performed fantastically, when you see what he has already achieved at his age - I was already 23 when I got into the Ajax first-team squad.
The Dutchman will be hoping that Courtois doesn't have such a fine game this Sunday as he is set to keep goal against his former club Manchester United, and they will be looking to bounce back from the disappointing 2-2 draw with West Brom on Monday.