Who is Carlsen's greatest opponent?

The following are Carlsen's classical game scores against the world's best players.

Aronian +8 -4 = 25

Kramnik +4 -4 = 12 

Nakamura +7 -0 = 15

Topalov +8 -3 = 5

Grischuk +2 -0 = 7

Caruana +2 -2 = 5 

Gelfand +4 -1 = 9

You left out Sergey Karjakin???

I think it is Kramnik

Scores mean very little against Carlsen, he is constantly improving himself, along with his confidence. If there was ever a worthy opponent for Carlsen, it is very hard to find now. We need a true champion, like Tal or Fischer, who dominates their opponents by early surprises. Long pressure games is not the way to go against Carlsen, and all good players seem to do that nowadays.

I think based on that, Ivanchuk probably is the player who pushed Carlsen to the most extreme. Remember the Candidates, Carlsen himself admitted it that Candidates was extremely tough...

Carlsen has 8-3 in wins against Ivanchuk though, and I wouldn't base too much on that game in the Candidates.

Ivanchuk in good form.

I think Carlsen's toughest opponents are the other young players, for some reason his scores are not at all that impressive against for example Giri, Nepomniachtchi and Vachier-Lagrave, but that may have to do with him playing so few games against them and the scores will become more "normal" later.

Anand was the greatest opponent when considered world champion, peak rating, amount of matches and losses.

+3 -1 =11

The last time he played classical games against them happened two year ago.

Man, if only other professional chess players would catch on to this "constantly improve yourself" thing.  Revolutionary.

McShane score 0 -1

Carlsen has never beaten Charo, so she must be his greatest opponent.

Carlsen's greatest opponent is Magnus Carlsen himself as long as he doesn't destroy himself he has a long time at the top

It may be surprising but the only one in world top 100 to have the best score against Carlsen is GM Andrei Volokitin... +0 - 4 = 2 ... Ccheckout the games, may be Andrei's play style doesn't suit him...

The last game played between the two happened five years ago.

His score against Mcshane is +3 - 1 = 2

Caruana or himself (Magnus Carlsen). My money bet "Magnus Carlsen"!

I'll go with himself at this point.

I personally think that Kramnik mught be his biggest opponent. He has uite a plus score against Aronian. Nakamura doesn't play well against Carlsen or Aronian, but has a good score against Kramnik. Andreikin, Nepomniacthi, and Karjakin also have a good score against Kramnik. He might have a problem with some of the younger players like Nepom and Giri, but not Karjakin. Nepom, Giri, and Volotikin aren't rated high enough to be serious competition against Magnus. Magnus doesn't really have a player that he usually loses against, unlike many other players. Aronian doesn't play well against Kramnik. Kramik usually doesn't play well against Nakamura. Caruana plays terribly against Nakamura. Nakamura plays terribly against Gelfand. Karjakin usually loses against Carlsen now. Anand was smashed this month.