BOSTON — Perhaps more than anything, last night’s series opener served as a referendum on just how well the youthful Hawks could hang with the Celtics. Needless to say, they passed the test.

The Hawks are one of the youngest teams in basketball with only two playoff veterans (Mike Bibby, Joe Johnson) and the team was clearly nervous about how all the youngsters would react. After falling behind by 13 points in the opening 10 minutes, the Hawks regrouped and showed they were willing to trade punches with the Celtics.

“They’re going to be a little bit nervous, but we told them it’s more intense and they’ll probably have more jitters,” Bibby said. “They’re fine. We have tough kids.”

Bibby said he remembered his first playoff game as a Sacramento King coming against Utah and its star guard, John Stockton. “That was nerve-racking. The first time down I threw the ball away and was, like, “calm down.”

The Celtics were certainly aware of the Hawks’ youth but don’t see that as an excuse to overlook anything. Coach Doc Rivers made sure to remind his team that athletic, young big men such as Al Horford, Josh Smith and Marvin Williams should be considered dangerous.

“A lot of these new, young guys there are very few players you can compare them to because they’re just so athletic. We haven’t seen the athletes like this, ever,” said Rivers.

As for his youngsters, Rivers made sure to compile extra film clips on DVDs and some thick scouting reports for the players to take home and study. How did the players take to the extra work?

“We give it to them and if they open it they’ll probably find $100 in one of those pages,” Rivers said with a smile. “Some guys do, some guys don’t. We just want you to be ready to play at the end of the day. Sometimes half that stuff will [mess] them up anyways. We just want them to focus on playing basketball. You give it to them because some guys do like reading.”

Last to begin NBA series

The Celtics and Hawks were the last NBA series to begin because the Boston Bruins were booked in the Garden on Saturday night for their playoff series with Montreal. The Bruins and Habs are tied, 3-3, heading into a Game Seven tonight in Canada, despite Boston being the eighth seed and the Canadiens being the top seed. That fact is not lost on the No. 1-seeded Celtics.

“I think it’s great,” Rivers said of the Bruins’ underdog effort. “I don’t know a thing about hockey but what I like is you can see a team that believes that it can win and that’s really neat to see,” he said.

Edge from the bench

Rivers went to his bench early last night in part because of foul trouble, but also because he feels his reserves give the Celts’ a legitimate edge. Leon Powe was the first man in and veteran P.J. Brown was a surprising sub once Kevin Garnett picked up his second foul late in the first quarter.

Powe has become a fan favorite for his tough effort in the low post, and his teammates say few players work harder.

“Leon has come as far as anyone we’ve seen in the last year,” Paul Pierce said. “Being a guy who was a second-round (draft pick) and a guy who in the first half of the season pretty much didn’t get off the bench to play much at all, he stuck with it and he started to reap the fruits of his labor. You see him every day in the weight room, working on the court. I don’t think there’s a better second year player in this second half of the season outside of Powe. Leon’s been phenomenal. He’s exceeded a lot of people’s expectations.”

Hawks in dangerous territory

The playoffs have never been kind to the Hawks. The franchise’s only championship came in 1958, when the then-St. Louis Hawks beat the Celtics in six games behind Bob Pettit and Cliff Hagan. Since moving to Atlanta in 1969, the Hawks have never played in the NBA Finals and haven’t appeared in a conference final round since 1970.

This is the Hawks’ first playoff appearance since 1999. The team finished 30-52 a year ago and improved to 37-45 this season.

The Hawks and Celtics last hooked up in the postseason in the 1988 conference semifinals. Rivers was a guard for the Hawks and a runningmate of Dominique Wilkins, now an executive with the team, on a team that lost in seven games. The final game was a 118-116 thriller marked by fourth-quarter explosions by Wilkins and Larry Bird.

“I did yell at him a lot. Usually it was saying ‘pass,’ ” Rivers said of Wilkins. “We are very close. That Game Seven has been brought up a lot (lately) and that’s not a great memory for me, honestly. To me it’s a very negative thought. We don’t bring it up.”

kmcnamar@projo.com