Miami sealed an NBA Eastern Conference semi-final sweep of Washington with a 99-95 victory to win the series 4-0.
Dwayne Wade was the Heat's main man once again in the absence of injury-hit Shaquille O'Neal, racking up 42 points.
He was unstoppable in the third period, shooting seven-for-seven from the field and eight-for-eight on free throws.
The 23-year-old guard said: "I felt like I couldn't miss. You just get into a rhythm - I got comfortable. I just got into a flow."
Wade broke the Heat one-game playoff scoring record of 38 set in 1997 by Tim Hardaway against New York, keeping Miami unbeaten in the play-offs.
"That was pretty unbelievable," Heat coach Stan Van Gundy said. "Dwyane was fabulous."
Wizards coach Eddie Jordan admitted: "He did a terrific job. He's a bona fide star in this league. He raised his game, especially with Shaq out."
O'Neal will have at least another eight days of rest before the Heat begin the best-of-seven Eastern Conference final against either Indiana or defending champions Detroit.
O'Neal averaged 22.9 points and 10.4 rebounds a game this season and was the NBA's most accurate shooter.
His replacement, Alonzo Mourning, got into early foul trouble and spent most of the first three quarters on the bench.
"We can't win it all unless the big guy is in there," Mourning said.