The Terps and Spartans clash Saturday night for the first time this season.
Ayala scored a season-high 16 points, sinking four 3-pointers.
"We didn't respect our opponent enough."
Smith also notched his seventh straight double-double.
Maryland enters the game as heavy favorites.
Maryland looks to build upon its lead at the top of the Big Ten.
Cowan got into foul trouble, but the Terps remained composed against Illinois.
The Terps rose to first-place in the Big Ten with victories against Rutgers and Illinois last week.
Guard Anthony Cowan contributed a game-high 20 points.
The Terps look to stay hot in a pivotal top-20 matchup.