DENVER — The Miami Heat now will have to flip the script. Having won their opening game of their first three series during this underdog run to the NBA Finals, the Heat for the first time this postseason will have to play from behind. Three days after an emotional Game 7 road victory to push past the Boston Celtics in the Eastern Conference finals, the Heat had the look of a team short on energy, height and shooting, falling 104-93 Thursday night to Nikola Jokic and the Denver Nuggets at Ball Arena. “This is a great challenge,” Heat coach Erik Spoelstra said.