Endgame player vs middlegame player: Is the result inevitable? I recently asked this question: Why Anand and Carlsen insisted on playing the same opening/defense

FM Rauan Sagit answered: 


  In my view, in terms of opening preparation, the Anand team failed to
  obtain middle game positions that suited Anand's style. In general, I
  think that Anand should have aimed for long middlegames with most
  pieces intact. While Carlsen should have aimed for long endgames with
  most pieces exchanged off the board. From this point of view, Carlsen
  got his types of positions, while Anand failed to get his. This can
  partially be explained by the chosen opening systems. Additionally, I
  think that Anand should not have willingly exchanged queens in a
  single game.


That got me thinking, when a strong endgame player faces a strong middlegame player, does the latter stand a chance?

The endgame player would force the opponent into exchanging pieces and there's nothing you can do about it simply because he doesn't care about his pieces, just like what happened in the championship match,  am I right? What are the odds of a middlegame player defeating an endgame player?
My point was that Anand could prevail in dynamic middlegame positions, while Carlsen could prevail in endgames with a minimal advantage. Of course, Carlsen masters all three phases of the game on a top level. At the same time, sharp and complex middlegame positions release more adrenaline and require more focus. Regarding comparing a middlegame expert and an endgame expert, it is not so easy to exchange pieces. An exchange of pieces is a mutual decision and it takes two to tango. One way of keeping most of the pieces on the board is to select opening systems accordingly. For instance, you can choose the Volga gambit

[FEN ""]
1.d4 Nf6 2.c4 c5 3.d5 b5


and most of the pieces will be on the board for a good while. In some systems, it is easier for the endgame expert to steer the game towards e.g. an early exchange of queens. While in other systems, it is much more difficult to steer towards multiple exchanges. That being said, all the professionals are experts in all three phases of the game. So the key is to steer towards positions where they risk the most and therefore create the situation they prefer to avoid.