Cavaliers Step Up Into Conference Finals : NBA playoffs: Daugherty scores 16 points in the first quarter as Cleveland beats Celtics.

The biggest game in the Cleveland Cavaliers’ history was one of their best.

Brad Daugherty scored 16 first-quarter points and the Cavaliers didn’t let up, beating the Boston Celtics, 122-104, Sunday and advancing to the Eastern Conference finals for the first time since 1976.

It was only the fourth time in 21 tries that the Celtics had lost the seventh game of a playoff series. They have a 6-2 record in seventh games in the Larry Bird-Kevin McHale-Robert Parish era, which may be coming to an end.

It marked a giant step forward in Cleveland’s recovery after more than a decade of mismanagement, missteps and injuries.

“It’s a great accomplishment. We’ve struggled with injuries throughout our careers,” Daugherty said. “People got traded. People got injured. Those types of things are disruptive. We’ve finally got everybody healthy, and now we’ll see what happens.”

The Cavaliers, perennial losers in the early 1980s, became competitive again soon after Wayne Embry became general manager in 1986. But they missed the playoffs a year ago, their season ruined by injuries that sidelined Mark Price and John Williams.

They turned it around this year, matching a franchise record with 57 regular-season victories.

Cleveland had been knocked out of the playoffs by Boston twice, and the Celtics forced a seventh game by handing the Cavaliers their worst playoff loss, 122-91, Friday night at the Boston Garden.

“We’ve been coming of age all year long, not just today,” Coach Lenny Wilkens said. “It’s been a steady growth process, getting guys back healthy, getting through the first round of the playoffs.”

“They just outplayed us,” said Larry Bird, who was hounded throughout the game by Mike Sanders. “They played better offense, better defense and moved the ball better. We just weren’t in the game.”

The Cavaliers shot 73% in the first quarter, alternately beating the Celtics on fast breaks and letting Daugherty dominate the half-court game. Price had nine points in the quarter, which ended with Cleveland ahead, 35-21.

Boston got no closer than 10 after that, and Cleveland blew it open by sinking 10 consecutive shots from the field in the third quarter for a 93-67 lead.

“We didn’t want to give those guys any extra opportunities, because they’re so good,” Daugherty said. “All week we’ve heard about the mystique, the tradition, the Big Three, all of that. They’ve been in this situation a lot of times, and they’ve played a lot of mistake-free basketball. It’s a tremendous accomplishment to beat them.”

The Cavaliers beat Boston in every phase, outrebounding the Celtics, 45-31; outshooting them, 59%-50%; handing out 42 assists to Boston’s 20 and blocking 11 shots to the Celtics’ four.

“That was one of the most disappointing games I’ve ever played in, given the importance of it,” McHale said. “A loss like this makes for a long summer.”

Daugherty had 27 points, nine rebounds, six assists and three blocks. Williams scored 20 and Sanders added 17.

Cleveland will play Tuesday night against Chicago, a 110-81 winner over New York in Sunday’s other semifinal.