The Boston Celtics lost Game 1 - and they may have lost their floor leader for Game 2. Josh Smith scored 22 points and grabbed 18 rebounds as the Atlanta Hawks built a big lead early, then held on for an 83-74 victory over the Celtics in their opener of the Eastern Conference playoffs Sunday night. But this one will be remembered for what happened in the final minute, not the Hawks' blistering start. While complaining about a call, Boston star Rajon Rondo was ejected for bumping an official and faces a possible suspension when the teams meet again Tuesday night in Atlanta. "I didn't intentionally chest-bump him, but that's what it appears to be," Rondo said. The Hawks, who led by as many as 19 in the first half, were clinging to a four-point lead when Rondo lost his cool with 41 seconds remaining. Boston's Brandon Bass was called for a foul on Smith tussling for a loose ball, with both players sprawled on the court out beyond the foul line. Rondo, who scored 20 points and dished out 11 assists, clearly appeared to stick out his chest to strike the official. That's a huge no-no and will almost surely draw the wrath of NBA Commissioner David Stern. Boston Celtics' Avery Bradley, center, puts his arm around Rajon Rondo, rear left, and walks him off the court as he is ejected from the game by referee Marc Davis late in the fourth quarter of Game 1 of a first-round NBA basketball playoff series against the Atlanta Hawks, Sunday, April 29, 2012, in Atlanta. The Hawks won 83-74. "It's out of my control," Rondo said. Obviously, I want to be there for my teammates but other than that, it's out of my control. Rondo had a similar take. Obviously I was upset about the call and I said some words to Marc. I deserved the first tech," Rondo said. As I was walking, I thought he stopped. My momentum carried me into him. I even think I tripped on his foot. At the beginning, the Hawks looked much quicker and faster than the aging Celtics. The Hawks twice pushed the margin as high as 19 points and settled for a 49-35 edge at halftime. Smith totally outplayed Boston's Kevin Garnett over the first two quarters, going into the break with 15 points, 11 rebounds and two assists. Garnett had only two points on 1-of-9 shooting. "He was an animal," Atlanta coach Larry Drew said of Smith. When he's playing with that energy, he just makes us so much better. Smith had to carry the load. The Hawks' other big gun, Joe Johnson, had a miserable night with 11 points on 3-of-15 shooting, committing more turnovers (four) than he made field goals. He was 0 of 9 from 3-point range. The Hawks got sloppy with the ball and made only 19-of-54 shots after their blistering performance in opening quarter. That allowed the Celtics to edge back into the game, and it looked as though they might just pull off the comeback until Rondo's big blunder. "We came out like our jerseys were going to win the game, because we're the Celtics," Rivers said. You've got to play to win the game.