Williams made 11-of-15 field goal tries, including 4-of-6 3-pointers.
Joe Johnson had 16 points and 13 assists and Al Horford had 16 points and eight rebounds for Atlanta, which has won six straight over Washington and swept the Wizards for the first time since the 1997-98 season.
Antawn Jamison had 23 points and nine rebounds for the Wizards, who have lost four of their last five games. JaVale McGee had 14 points and nine rebounds and Andray Blatche and Darius Songaila each had 12 points for Washington.
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