Heat 107, Nets 86: LeBron James scored 22 points and Ray Allen made four 3-pointers while scoring 19 points as host Miami defeated Brooklyn in the opening game of the Eastern Conference semifinals.Chris Bosh added 15 points and 11 rebounds and Dwyane Wade scored 14 points for the second-seeded Heat, who host Game 2 on Thursday. Mario Chalmers added 12 points for Miami, which shot 56.8 percent from the field and held a 52-28 edge in points in the paint.Joe Johnson and Deron Williams scored 17 points apiece for the Nets, who were 4-0 against the Heat in the regular season. Veteran Paul Pierce had just eight points as Brooklyn was unable to keep up with Miami in the second half.It was a 13-point margin with less than nine minutes remaining before the Heat began stretching it out. Allen drained two 3-pointers in an 81-second span as the advantage reached 94-74 with 5:33 remaining and Miami's lead topped out at 23 points. The Heat led by as many as 11 points in the second quarter before Brooklyn cut it to 46-43 on Williams' 3-pointer as time expired in the half. Miami used a 15-2 burst to open up a 16-point lead with just over four minutes left in the third before Williams again beat the buzzer with a 3-pointer to pull the Nets within 79-66 entering the final stanza.GAME NOTEBOOK: Heat F Chris Andersen had seven points, four rebounds and four blocked shots before leaving in the fourth quarter due to a knee injury. X-rays were negative. … Nets F Kevin Garnett (123 appearances) went scoreless in a playoff game for the first time in his career. … The 29-year-old James is the youngest player - and eighth overall - to reach 4,000 career postseason points.