Hi,
In that knight's pawn position I like to use the passive defense placing your rook on the last rank. Not because I like to play passive, but because your rival in his desperation can fall for a very nasty trap that can make him/her lose the game inmediately, and that is pushing the pawn to the 7th rank, as follows:
This is being taken from the book Basic Endgame Strategy written by Bill Robertie.
Study of the endgames where one side has a Rook and a lone pawn, while the other side is defending with just a Rook. These are tricky endgames.
The Basic idea is this: The defender wants to get his king in front of the advancing pawn, If he can do that, he shall most probably get the draw. The winning side tries to use his Rook to keep the defender;s king cut off from the pawn, either along a file or a rank. If the defender's king can't get to the pawn, He'll mostly lose.
This is the engame study taken from the book "Basic endgame strategy" written by Bille Robertie.
If you can get your king in front of the enemy pawn, you should be able to draw the game by playing alertly. Let's see just how it is done. As you can see that the pawn is heading towards the end of the g-file to queen, but white king has managed to reach the queening square g1. Can black force the pawn through? Not if white knows what he is doing.
Here's how white should play to secure the draw. 1.Rb3 ! This is the critical idea. White's rook guards the third rank,making it impossible for black to move his king there. If black does nothing. White just shuffles his rook along the third rank, holding his position. What can black do? He could try checking: 1...Ra1+ 2.Kg2 Ra2+ 3.Kg1 Well that didn't accomplish much. If he moves his rook along the secnd rank, white just moves his rook along the third rank: 3...Rc2 4.Ra3 Rb2 5.Rc3 This isn't going anywhere. The only serious try is to push the pawn. 5...g3
Now black has a real threat. He plans to plays Kh4-h3 and Rb2-b1 checkmate.
Can you see how to stop the plan? 6.Rc8 This is the second half of the white's idea. When Black advances his pawn to third rank, white moves his rook back to the eighth, and starts checking the king. Because black's pawn is occupying a key square on the third rank, he won't have anyplace to hide from the checks. 6...Kh3 7.Rh8+ Kg4 8.Rg8+ Kf3 9.Rf8+ Ke4 10.Re8+ Where can black's king go? ther's no hiding post from the checks. If the king goes back toward the pawn, white just keeps checking. If he tries to run back toward the rook- 10...Kd5 11.Rg8 White just stops the checks and goes back to capture the undefended pawn. 11...Rb3 12.Kg2
Next turn white captues the pawn with his rook and the game is a draw. Conslusion: White started controlling the third rank with his rook to prevent black from moving his king there, creating checkmating threats.Once Black was forced to put his pawn on the third rank, he had no hiding places from the checks.