sometimes it could not just be explained by luck

no matter how artistic your coach's strategy is , it has to executed by players. That's true.

But a good plan, the confidence and the calmness might not exactly win a specific game for you, but in a long run, it would be paid off. I don't think MU rallied to win the 1999 Champion league's champion in stopage time was just a pure luck. Of course, still lucky enough even he made the right substitution, but you just can't deny the credit Sir Alex deserved.

As to LBJ's magic shot, it's a combinaiton of his ability and luck. At that moment, it is no one's fault. but would it be better if Magic could find a way to keep his away from receiving the ball? that might be debatable.