A storyline of this season has been how a Celtics team with a few of the parts that made it so successful in the past continues to chug along.

Among the lesser highlights are the players who support the main pieces of what was a championship team just a few years ago.

Kevin Garnett, Paul Pierce, Ray Allen and Rajon Rondo may be the source of guts, production, leadership and bravado for the Celtics, but the roster is still 12 deep. Celtics head coach Doc Rivers was just as persistent developing the rest of the team as he was coaching the stars this season, and playoff time is when he gets to see whether that attention can reap benefits.

Greg Stiemsma and Ryan Hollins were among those who had their glimmers of glory for the Celtics this year. Stiemsma rose from a mostly unrecognizable player to earning key minutes. Hollins has been working his way toward being a dependable big man for a Celtics team that always needs more rebounding and defense.

On Monday night, the Celtics looked sluggish for most of the first half as the Sixers consistently moved the ball and executed scoring chances. Both Stiemsma and Hollins were called on again. This time, they made their mark on playoff basketball.

"Hey, listen," said Kevin Garnett, who thwarted the 76ers again with 20 points. "Stiemboat, Ryan, [Brandon Bass] played really, really well. They were the determining factors of the game. They made all the energy plays. In the first half [the Sixers] had a nice rhythm, and in the second half we did a better job of distorting that rhythm. Those guys were the reason for that."

"Energy" was definitely the right word. Stiemsma made his first appearance in the game about halfway through the first quarter, and he immediately started scoring easy baskets to keep the Celtics moving against Philadelphia, which had surged back from an early deficit.

"The 10 points by the Steamer on the first half, or the six points, whatever he had was big," Rivers said. "Just all the little baskets, just to keep us around, because, strange to say, but you felt like there was a chance early on that they could stretch this game if we didn't get it right."

Stiemsma's playoff production hasn't been superb so far. He's struggled to hold his own in the Celtics' defensive sets, a trend that continued Monday.

"I thought I missed my defensive assignments early. But then I got those buckets, and that really slows the game down, really makes you feel more comfortable," he said of his 10-point, three-block performance in which he was 5-for-5 from the field on mostly dunks and layups. "Tonight was just another opportunity. It's been like that the whole season. Just got some looks early and got myself going."

Rivers said his team was dealing with "mental traffic" as the game began, a syndrome not helped by the mostly empty stands as fans filtered in late to the 7 p.m. start.

"I thought Philly had great energy. I didn't think we did," he said. "I thought the beginning of the game, you could see they were free. They were playing with a great spirit — you could see that. I didn't think we were matching that."

Stiemsma's entry into the game didn't immediately turn the tide, but it kept the Celtics close. The 76ers were leading the rebounding battle and limiting the Boston offense, and they could have taken a big lead into the half. But Philadelphia came out of the break ahead just 50-47.

In the third quarter, Bass and the rest of the team turned it up on both ends, and the 12-point advantage the Celtics had in that frame propelled them to the win.

"Our bench does an amazing job," Hollins said. "We know we need to pick up the stars, pick up the slack. It's not just points. It's not just on the stat sheet — the energy you have to [have] and, you know, help the Big Four. [That] can really help our team."

Hollins provided his own spark a couple of minutes into the second quarter, when he came in to spell Stiemsma. He and Mickael Pietrus were on the court for a good chunk of the frame, and the Celtics recorded a couple of strong defensive stops while the offense got the C's within a point of the lead.

By the time the Celtics returned to the floor for the third quarter, the team was ready to go.

"We weren't playing our type of basketball" in the first half, Hollins said. "We were in the game, kind of close, but we weren't playing Celtic basketball."

Bass started the spurt in the third quarter that put Boston ahead for good, but the bench was in the mix again.

Stiemsma came in partway through the quarter and logged a basket and block that kept the run going. Pietrus hung in for key minutes in the fourth.

After a playoff series that looked to swing heavily toward the services of four choice superstars, the effort was a reminder that in the long race of postseason basketball, everyone will be called on to contribute sometime.

"It's playoff time, so as long as we're winning, I'm happy," Stiemsma said. "I feel like I wasn't quite playing the way I was at the end of the year."

On Monday night, he was playing a little better.