Washington had replaced its starters after building a 62-39 early in the third period, but Miami came within 86-70 before Antawn Jamison scored six straight points for the Wizards to stifle Miami's fourth period comeback.
Caron Butler had 16 points, six rebounds and five assists. Jamison had 15 points and nine rebounds.
Roger Mason scored 12 points and Darius Songalia 11 for the Wizards, who beat Miami for the second time this month. They had lost four of their previous five games.
Miami was led by Ricky Davis' 22 points, four rebounds and three assists. Luke Jackson scored 14 points and Dwyane Wade -- one night after a career-high 48-point effort -- was limited to 12 points with six assists for the Heat, who have lost four in a row.
They played without center Shaquille O'Neal (hip) and guard Jason Williams (knee).