Kill the rook

Sayali and Gargi are playing chess. They decided to play it in an unusual way by setting their own rules. Sayali has only one rook and Gargi has only one knight. Now, the task for Gargi is to win the game by killing the rook in minimum number of moves. 1. Chessboard is like normal chessboard of total 64 blocks,8*8 grid of 32 white and 32 black blocks. Consider leftmost bottom corner block as (0,0