Fischer Overlooks a Theoretical Draw

After looking at four positions in Fischer - Keres, Zurich 1959,
I thought it was time to move on to the next game. Then I realized I hadn't looked at the 'obvious discrepancy' 41...Be6 {BF: !; GK: ?} flagged in the original post. The position preceding the move is shown in the diagram.

Of 41...Be6, Fischer wrote, 'Sacrificing a second Pawn for counterplay on the open c-file. On 41...Ke5 42.Ra7 keeps Black tied up.' Kasparov disagreed,

Fischer attached an exclamation mark to the move in the game, but after it White could have won. Therefore the correct move was 41...Bf5! 42.Bxf5 Kxf5 43.Rxd6 Ke5 44.Rb6 d3 45.Rxb5+ Kd6! 46.Rb4 (46.Rb3 Re2+ 47.Kf1 Re3!) 46...Re2+ 47.Kf1 Kc5 (Huebner), when Black saves himself in the Rook ending.

The passed d-Pawn generates enough counterplay to save Black.

Zurich 1959
Keres, Paul

Fischer, Robert
(After 41.Ke2-f2)
[FEN "8/3br2p/R2p1k2/1p6/3p1p2/5P1P/PP3KP1/1B6 b - - 0 41"]

Kasparov offered the following variations and comments after 47...Kc5:

• 48.Rb7 Rc2! (with the threat 49...Rc1+ 50.Kf2 d2) 49.Rc7+ (49.Rd7 Kc4) 49...Kd4 50.Rxh7 Rc1+ 51.Kf2 Rc2+; or
  
  
• 48.Rxf4 Rxb2 (again threatening 49...Rb1+ 50.Kf2 d2) 49.Ke1 Rxg2 50.a4 Ra2 and the limit of White's dreams is a theoretically drawn endgame with f-and h-Pawns; or
  
  
• 48.Rb3 Kc4 with a draw.
  
  
• Huebner's move 48.a3? even loses after 48...Re3! 49.Re4 d2 50.Rxe3 50...fxe3! [MW: Is 50...d1=Q+ 51.Re1 a fortress?] 51.Ke2 Kc4.

I especially liked the phrase 'the limit of White's dreams' to describe the theoretical draw.