Martell Webster and Chris Singleton combined for 40 points, leading the Wizards to a 101-94 win over Miami.
Washington trailed by 14 at the half, but with Lebron James sitting out the fourth quarter, the Wizards fought all the way back. Dwayne Wade led Miami with 23 points, Chris Bosh added 18 and James finished with 13.
"We came out in the third quarter and turned the ball over too much," James said. "That allowed them to get back in the game. We can learn from every game, no matter if it's preseason."
Washington wraps up exhibition play on Friday night in San Antonio. The regular season tips off on Tuesday with the Wizards in Cleveland.