Unlike most chest-bumps executed on a basketball court, there was nothing celebratory about Sunday's contact between Rajon Rondo and referee Marc Davis.

A day later, the Celtics were certainly not in a festive mood following a ruling from the NBA.

The league suspended Rondo on Monday for one game, without pay, for making contact with a game official. The all-star point guard will miss Game 2 of the Eastern Conference playoff series with the Hawks on Tuesday. It is the second suspension for Rondo this season for his conduct toward an official.

Rondo bumped Davis with 41 seconds left in the Celtics’ Game 1 loss to the Hawks Sunday after being assessed a technical foul for arguing a call. He was immediately whistled for a second technical and ejected. Rondo said he was upset because officials called teammate Brandon Bass for a foul, instead of awarding a jump ball, during a scrum for a loose ball with Hawks forward Josh Smith.

“It’s part of the package with our team,” Celtics coach Doc Rivers said Monday prior to be informed of the ruling. “We are a volatile team in a lot of ways. Rondo is an emotional player. You know the old saying, I would rather kindle a fire than start one. I like his fire and sometimes he burns you. I like the fire that he has.

"Someone asked, why was he involved [in arguing the call]. Because he is into the game. He is a fighter for his team. You didn’t want him to go that far, obviously. It’s just who he is. It’s also what makes him great. It’s that fine line that you have to walk and every once in a while, he crosses it.”

Rondo and Rivers said following the game that the contact with Davis was unintentional and that his momentum carried him into the official. Teammate Paul Pierce called the contact “real minor” Monday.

However when league security spoke to Rondo Monday morning, a suspension was imminent. It came in the late afternoon.. NBA rules are clear on contact with game officials.

“We have a hard and fast rule. Unless someone trips you and sends you into him, you don’t touch a referee,” NBA commissioner David Stern told ESPN radio prior to the announcement.

Rondo was unavailable at the team’s practice Monday. He had 20 points and 11 assists in the series-opening loss to the Hawks. The Celtics have had to play without Rondo this season. He was suspended for two games in February for throwing a ball at an official. He also missed three games in the final week of the season, including one against the Hawks, with a sore lower back.

It leaves the Celtics without one of the league's premiere play-makers. Rondo led the NBA is assists this season and has a streak of 25 games with 10 or more assists. It’s the longest streak since the Jazz’s John Stockton did it in 29 straight games in 1992.

“For our shooting bigs, he gets them open looks,” guard Keyon Dooling said. “For our shooters from the wing, he gets them open looks. Not having him in there, we’ll rely more on Paul [Pierce] scoring, Kevin [Garnett’s] post-ups.”

Aside from Avery Bradley bringing the ball up court and running the point, Rivers insists the team’s offense will not change.

“We pay everybody,” Rivers said. “We just don’t pay five or six guys. We pay the entire team. We pay them to be ready. … We are going to need an extra starter and an extra guy off the bench. Someone is going to have to step up for us.”

Bradley scored 28 points against the Hawks on April 20, when the Celtics were without Rondo, Pierce, Garnett, Ray Allen and Mickael Pietrus. The Hawks narrowly won that game 97-92.

“Certainly whether he is there or not, we can't let our guards down,” Hawks coach Larry Drew said. “… Like I told our guys, this is the playoffs and there are things that happen throughout the course of the playoffs that can change things. But you can't at any time relax or let your guard down. You have to be a team on a mission.”