They were leading in the first half but can't hold it due to their lack of role players, Smart and Horford are absent which they really need the most to play great defense and fastbreak points. The Miami Heat see this hole in the second half which lead them to further cut the lead and finally buried the Celtics with threes. Jimmy Butler is doing his best in this series as well, scoring 40+ points in the conference final something praiseworthy especially when you won from such strong defensive team.