Your strategy will be allowed to bet when runner by position 1 loses two times in a row. Runner by position 1 is always first player e.g. Pellegrino v Giustino then Pellegrino is runner by position 1.
It is best that you test this in simulation mode to see if it works like you want it to. You should know that match will probably end if runner loses two sets, unless it is a three set match.