Duke (28-4) reached the semifinals of the Atlantic Coast Conference tournament and increased the chances of a title game rematch with North Carolina.
North Carolina beat Duke last Saturday to win the regular-season championship and the Tar Heels rallied earlier in the day to edge Miami in the first of the quarterfinal matchups.
Duke held Maryland without a point for more than 5 minutes of the second half to pull away. Seth Curry and Ryan Kelly each had 11 points for the Blue Devils, who are seeking their third straight conference tournament title.
The victory was tempered, however, by the loss of senior guard Nolan Smith in the second half due to a toe injury. His status for the remainder of the tournament was not immediately known.
Maryland (19-14) was led by 16 points and 16 rebounds by Jordan Williams. The Terrapins are expected to miss the NCAA Tournament.