marcusantoinerome: <saffuna> The classic case that I am familiar with is Bronstein-Botvinnik WCh 1951. In Botvinnik's book on the match, his notes to Game 1 read - after 1. d4 e6 2. c4 f5 - Botvinnik vs Bronstein, 1951
"So, the Dutch Defence. And this is no accident.
In this match my opponent normally employed those openings that I had usually chosen earlier. He apparently thought that he would force me to fight against my 'own' systems...
Such a 'method' seems to me to be rather naive, if it was not forced. It was probably all based on the fact that Bronstein did not have anything significant prepared, and in the given instance this variation is not bad. The results, however, could not be good - I was force to play openings which I knew quite well; of course, this made things easier for me, if it is taken into account that for three years I had been cut off from chess."
Bronstein doesn't agree. In "Chess Improviser" by Vainstein, Bronstein comments on the above quote:
"It is this point which is inexplicable to me. If Botvinnik considers that the result of the match, +5-5=14, was not a good one for me, what score was he reckoning on, had I not 'abused' the Dutch Defence and others of his favorite openings?
In connection with this, I recall something else said by Botvinnik - that after the adjournment I lost three completely drawn endings against him. He has in mind the incomprehensible errors in the 6th, 19th, and 23rd games. Here Botvinnik is perfectly right, but these mistakes deep in the endgame can in no way be put down to an unfortunate choice of opening...
It therefore follows that, had it not been for my oversights in these three endings, the score of the match would have been +5-2. I could not have hoped, of course, for anything better. Thus logic suggests that in the opening I was well prepared, as I think that the reader will be able to convince himself in the analysis of the games."