When one player has enough material to mate his opponent, his opponent doesn't have enough material to mate him, and his time runs out, it is considered a draw by insifficient material.
Insufficient material

But time ran out for the player that had enough pieces to mate the other player, not the other way around.
It is quite simple, if both sides have insufficient material to mate their opponent, the game is automatically drawn. If your time runs out, but the other player has insufficient material to mate you, instead of losing the result is a draw.
I watched 2 games that ended with an "automatic" Insufficient material. I both of those games time had run out on one of the players. What does one do in a disputed case like that? Also in both cases one player clearly had enough pieces to mate the other player (given time).