BOSTON — LeBron James and the Cleveland Cavaliers only needed one quarter to elbow their way back into the lead of their Eastern Conference semifinal with the Boston Celtics.

James scored 21 of his 38 points in the first quarter to help Cleveland beat Boston 124-95 last night, handing the Celtics their worst home playoff loss ever and taking a 2-1 lead in the best-of-seven Eastern Conference semifinals.

"It started with me tonight. Everyone else saw my aggression and took advantage of it," James said. "I think rest helped me; rest helped all of us, and we were able to put together a complete game for the first time in these playoffs."

Showing no ill-effects of an elbow problem that was the talk of Cleveland during the three-day layoff since a Game 2 loss at home, James finished with eight rebounds and seven assists. The 21 points in a quarter was a franchise postseason record.

"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. "We knew how important it was to come out and play aggressively after giving away Game 2."

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. The Cavaliers shot 67 percent from the field in the first — and 59 percent for the game — and Boston was never able to recover. The Celtics' previous worst home playoff loss was 97-70 to Indiana on May 7, 2005, in Game 7 of the first round.

"It was great to see LeBron set the tone from the jump," Cleveland coach Mike Brown said. "And the rest of the team followed."

Game 4 is tomorrow, 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 clincher against Chicago. But he went 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 think he's healthy," said Celtics coach Doc Rivers, who has been dismissive of James' injury. "His elbow looked very good tonight. So enough with the elbow injury. I think we can go ahead and focus on basketball."

SUNS 110, SPURS 96

The Phoenix Suns would be thrilled to finally beat the San Antonio Spurs in the playoffs by any margin.

But a sweep? That would be especially sweet.

Phoenix is one win away from ending years of playoff misery against San Antonio, taking a 3-0 lead in the Western Conference semifinals with a victory last night, putting the Spurs in a historically irreparable hole.

"I think it's safe to say that may have been the best fourth-quarter performance I have ever seen in a playoff game," Suns forward Grant Hill said.

He wasn't talking about the team.

He was just talking about Goran Dragic.

The backup point guard scored 23 of his 26 points in a brilliant fourth quarter, rendering Steve Nash unneeded until the final 3 minutes. Amare Stoudemire? He never even took off his warmups in the fourth quarter.

Dragic hit nine of 11 shots in the fourth, including all four 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.

"He's my secret weapon," Suns coach Alvin Gentry said. "I don't know where he came from, either."

Game 4 is tomorrow night in San Antonio.

Manu Ginobili led the Spurs with 27 points.