Black to play and win
K O'Sullivan v A Van Tets 1973
Therefore, 1….Ra3! is the move, and even with a few minutes on the clock, or less, it is clearly better than 1…Rc8: the ending after swapping off on c5 and b3 must be better than the ending after 1…Rc8.
In fact, the win is trivial: the f4 pawn drops off, black's e6 pawn can be defended if white biffs it, so 0-1.
Briefly, back to 1…Rc8, since there is a nice line. Say 2 Ke3 (marking time) 2…c4 3 Rc2 (marking time)
What happens if black plays 3…cb or 3…c3
If Black is sharp enough to see 3…cb 4 Rc8 c2 (and the rook can't prevent the pawn from queening; or if black pushes his pawn forward with …c3, intending either to reinforce if with …b4, if permitted, or if white plays b3-b4, to then come in…