LeBron James scored 21 of his 38 points in the first quarter to help the Cleveland Cavaliers beat Boston 124-95 Friday, handing the Celtics their worst home playoff loss ever and taking a 2-1 lead in the best-of-seven NBA Eastern Conference semifinals. Showing no ill-effects of an elbow problem that was the talk of Cleveland, James finished with eight rebounds and seven assists. The 21 points in a quarter was a franchise postseason record. Antawn Jamison had 20 points and 12 rebounds for Cleveland, while Shaquille O'Neal added 12 points and nine rebounds. Rajon Rondo, who had 19 assists in Boston's Game 2 victory on Monday, had 18 points and eight assists. The Celtics missed 10 of their first 13 shots, hitting just 27 percent in the first quarter to spot Cleveland a 21-point lead. They were never able to recover as the Cavaliers shot 59 percent from the field for the game. Game 4 is Sunday and the Celtics need a victory to split their home games and assure themselves of another. James wore a black sleeve on his right elbow, which became a concern after he shot a free throw left-handed in the closing minutes of Cleveland's first-round playoff game against Chicago. He was 8 of 10 from the field in the first quarter - most of them mid- to long-range jumpers - and after that it didn't matter. “I know I'm going to hear a lot about the elbow, but I'm here to play basketball and give our team a chance to win,” James said. The Celtics had high hopes after taking Game 2 in Cleveland to swipe the home-court advantage from the 61-win Cavaliers. But Cleveland earned it back in Game 3, needing just one quarter to silence the Boston crowd. “We knew how important it was to come out and play aggressive after giving away Game 2,” James said. Suns 110, Spurs 96: In San Antonio, Goran Dragic scored 23 of his 26 points in the fourth quarter to help Phoenix to a 3-0 series lead over San Antonio in the Western Conference semifinals, putting the Spurs in a historically irreparable hole. The Spurs have put Phoenix through a decade of postseason misery, ousting the Suns from the playoffs four consecutive times since 2003. One more win will end all that. They can thank Dragic, whose brilliant fourth quarter made it unnecessary for Steve Nash to get off the bench until the final 3 minutes and Amare Stoudemire to sit out the fourth quarter. Dragic hit nine of 11 shots in the fourth, including all four of his 3-point attempts. After his last one with 5.7 seconds left, the Suns impatiently waited for the final seconds to tick away before swarming Dragic as the Spurs shuffled away. “Coach said ‘Don't be shy, just be aggressive, attack the basket,”' Dragic said. “Third and fourth quarter, I just did it.” No team has ever come back from a 3-0 deficit in a best-of-seven series, and the way the Suns have played in this series, San Antonio might be struggling to find a way to beat them. Game 4 is Sunday in San Antonio.