The American star needed only 64 minutes to humble the tournament's top seed, firing 14 aces en route to her 13th straight match victory while claiming her second title of the year.
Williams, who also won last month's Charleston event, collected her 41st career crown -- tying her for second among active players with Kim Clijsters -- and fifth on a clay court.
Azarenka, meanwhile, ended as the Madrid runner-up for the second straight year and fell to 1-7 lifetime against Williams, including five straight losses.
2014: The Year in Fashion [PHOTOS]
LeBron James reveals his new Nike shoes