Backcourt or not?

[assignmentmaker]

The following protocol appears to work just fine for BktBallRef's Backcourt Quiz:

1- Team A must have team control.
2- The ball must have attained frontcourt status.
3- A player from team A must be the last player to touch the ball before it
enters the backcourt.
4- A player from team A must be the first player to touch the ball after it
enters the backcourt.

but how might it be apply in the following situation?

The ball is being passed among teammates on Team A in their front court. B1 tips a pass such that the ball flies up and over the backcourt. A1 steps into the backcourt and catches the ball before it hits the floor. Backcourt or not, and why?