Nunn's Chess Endings Vol 2-Rook Endings-The 5th Rank Cut-Off

Nunn's Chess Endings Vol 2-Rook Endings
The 5th Rank Cut-Off

Sadly, I have owned this fine book for a couple of years and not dared to open it.

Nunn's Chess Endings Vol2

Here is one of the games (Jussupow,Artur-Tseshkovsky,Vitaly Moscow 1981)  Nunn used to illustrate the 5th rank cut-off technique. I looked at the whole game to get a better idea of what happened and improve my endgame knowledge. 

Here is more on Jussupow



Here are my findings.

Jussupow,Artur (2575) - Tseshkovsky,Vitaly (2530) 
English Opening 1.c4 Nf6 2.Nc3 c5 3.Nf3 d5 4.cxd5 Nxd5 5.e4 Nb4 [A34]
Moscow-4teams Moscow (4.2), 26.02.1981

Position 1

Black has an active king+rook and is pushing the c-pawn for the win. What do you recommend for black now?

Black to Play

43.g3