By far the Heat and Lakers had their finest defensive performances of the playoffs in Game 4 this past Tuesday. The Heat getting star defender Bam Adebayo back and playing  more man-to-man defense were keys. 
After giving up an average of 120 points in the first two games, the Heat have held LA to an average of 103 points during the past two games. Heat coach Erik Spoelstra isn't going to go away from his defensive script from the last two games in which Miami has gone 1-1 SU, 2-0 ATS. The Heat are going to stick with plain, old-fashion playoff intensity defense. 
Adebayo's impact can't be downplayed. He missed Games 2 and 3 with a stiff neck. Adebayo is a rim protector and is the one Miami player who can keep Anthony Davis from dominating the offensive glass. Davis failed to get an offensive rebound in Game 4 after pulling down 13 during the first three games. 
It takes two to make a total work. I see the Lakers holding up their end especially with Goran Dragic out after he tore the plantar fascia in his left foot during Game 1. That's a serious injury and Dragic isn't coming back soon from it. The ramifications are severe for the Heat. Dragic, not Jimmy Butler, was the Heat's leading scorer in the playoffs entering this series. He also was their top assists guy and one of their key 3-point shooters.  
The loss of Dragic forces Spoelstra to use sixth man Tyler Herro as his lead ballhandler. Inserting Herro into the starting lineup greatly weakens Miami's bench especially from a scoring perspective. 
Lakers coach Frank Vogel made a major adjustment in Tuesday's Game 4 putting Davis - the Lakers' best defender - on Butler for the entire game. Butler still had a decent game, but couldn't come close to matching his Superman performance in Game 3 while missing nine of his last 12 shots. 
These adjustments, coupled with playoff intensity, should result in the Under cashing again.