You cannot be a really strong chess player unless you know how to play endgames.
This simple statement was a cornerstone of the Soviet school of chess. There was even a well known Russian chess saying: "С молодёжью - в эндшпиль!" -- which can be roughly translated as "when you play against a youngster, go straight to an endgame!"
Endgames are probably the most neglected part of the game, since all chessplayers spend most of their time on openings!
And yet we can expect that the best players know at least some very basic endgames. But just like the middlegame trap that Super GMs cannot avoid (we analyzed it here), there is also a certain endgame that the elite players fail to play correctly.
Indeed, what can be simpler than an endgame "rook + pawn vs. rook", right? Well, let's see...
This is a basic draw, which you can find in any book about endgames. Also, this is a good example of "do nothing." Black just keeps his rook on the e-file and White cannot do much. Here is how the game could continue:
Instead, Magnus Carlsen ruins this simple and well-known fortess by his next move. To be fair, the position is still a relatively simple draw...
Now, can you play better than 2700+ grandmaster?
And let's see what happened in the actual game:
I recommend you to remember an important position from this game:
As you can see, White's rook controls the back rank and the distance between Black's rook and White's king is only two squares.
For a successful defense, a rook needs at least three squares between it and the opponent's king. Now, can you help the former world championship challenger Nigel Short to win the following endgame?
And now look what happened in the actual game:
The mistake made by really strong chess players in these games are unexplainable.
I hope if you, my dear readers, get this kind of endgame, you'll play it better than super grandmasters!