Pogonina vs Chess.com Move 27. ...
Done, not much to say here. Expecting 27. ... Rc6
To the game: http://www.chess.com/votechess/game.html?id=14051
I did not really like 26. ... Rb8. I found that a move like 26. ... g6 was a better waiting move. The placement of Rb8 also gave White a tempo with Be2 since Bxa6 hangs the rook.
On the other hand, the counter strike against the a5-pawn was interesting and getting the rook out before Bd8 made sense. The single father of the counter attack on a5 was to my knowledge ivan_the_truble.
Now Black has to move Rb8 anywhere along the 8th rank or guard with Rc6. Rb8 can prepare b6/b5, so Black would not like to retreat so soon. The most active move is therefore Rc6 which also makes b6 accessible.
I haven't seen any other move discussed and no other move have entered my mind. Nevertheless, never expect the expected in chess or never do the obvious without a thought. The only other option that makes sense to me is Rc8. It is passive though and Ra4-b4-b6 together with the expected tresspassing of the white bishop will eventually choke Black. So what little hope glimmers depends on the weakness of the white a-pawn and the b6/b5 push.