WALTHAM, Mass. — The tested will welcome the rested when the NBA Eastern Conference finals begin tonight at TD Banknorth Garden.

Tested by Atlanta and Cleveland in consecutive seven-game series, the Boston Celtics will return to the parquet against the Detroit Pistons, rested since their 4-1 second-round triumph over Orlando last week, for Game One of a showdown that most basketball observers have expected since last October.

This is Boston’s first trip to the conference finals since 1992 and only its second since 1988, the year that marked the beginning of the end of the Larry Bird, Kevin McHale and Robert Parish Celtics. Coincidentally, the ’88 Celtics lost to the Pistons in six games.

The new Celtics, led by a new Big Three, will have had 48 hours to recover from their 97-92 Game Seven victory over the Cavaliers Sunday and prepare for the challenge the Pistons will present.

This is Detroit’s sixth consecutive visit to the conference finals, but only Richard Hamilton, Chauncey Billups and Tayshaun Prince were on the roster when the run started against New Jersey in 2003. Still, no franchise in 20 years — 1984-89 Lakers were the last — has achieved that mark.

The Celtics captain Paul Pierce, Sunday’s hero with his 41-point performance, is confident that his team will make the transition from Game Seven to Game One beginning without a letdown.

“I don’t think it’s going to be difficult as long as we keep our eyes and our minds on what our goals are,” he said yesterday after a light workout. “Yesterday, the fans got a treat, great series, everything you could have wanted out of a Game Seven after such a brutal one through six games. It’s great. Guys are full of emotions with a great win, but we’re trying to stay on target on what our goals are, and that’s being in the Eastern Conference final and hopefully ending up in the final.”

Center Kendrick Perkins had a different take.

“It’s hard, man, but you just got to go to your book or watch film and try to study as much as possible. This first game is key. You get to learn guys, and stuff like that. As the series goes along, you know it will start to get better,” he said.

The Pistons have a strong seven-man rotation. Like the Celtics, they have four players scoring in double figures in the playoffs: Hamilton (21.5), Prince (16.0), Billups (15.8) and Rasheed Wallace (13.9). Antonio McDyess (7.5), Rodney Stuckey (7.3) and Jason Maxiell (5.4) complete the rotation.

Kevin Garnett (20.3), Pierce (18.7), Ray Allen (12.7) and Rajon Rondo (11.1) lead Boston.

What concerns Pierce the most about Detroit?

“Just their all-around depth and experience and being there before, a team that’s won a championship knows what it takes. So those are some of the things that you think about, and knowing down the stretch you got a team that’s poised, and been through the tight games and this type of situation,” he said.

Having battled Cleveland superstar LeBron James for seven games, including their memorable shootout in Game Seven — James scored 45 points to Pierce’s 41 — Pierce is not concerned about running against Prince.

“Nothing against Tayshaun Prince, but LeBron, there’s much more to him. I think with Detroit, they emphasize more team basketball, so [Prince] doesn’t put as much pressure on you every time down the court as LeBron does.”

Pierce said he felt like he had been in a boxing match when he awoke yesterday.

“Every part of my body was sore, from my hip to my legs to my ankle, shoulder . . . I definitely feel the effects of Game Seven . . . Lot of bumps and bruises,” he said.

The Celtics won the regular-season series, 2-1. The teams split in Boston, and the Celtics won in Detroit.

Those three regular-season encounters were intense, but as Pierce said, “It just means so much more now. Both teams are vying for a spot in the championship game now. You notice how intense those games were. You expect it to go to another level. You expect another physical, brutal series because the Detroit Pistons are the team of the Eastern Conference over the last five or six years. If you want to get there, you got to go through them.”

Each proved itself capable of winning on the road during the season, but in the playoffs the Celtics are 0-6 away from the Garden, 8-0 at home. Detroit won a quarterfinal game in Orlando and has lost only three times in the postseason. Will Boston’s home-court advantage counter the rest the Pistons have enjoyed, especially Billups, who missed the last two games of the Orlando series with a strained right hamstring?

“Both are important,” Pierce said. “I mean, it’s good that we got home court. I’m sure it’s great for them that they got rest. It’s good that we didn’t have a travel day, especially after coming through a series like that.”

mszostak@projo.com