BOSTON (AP) _ Kevin Garnett took a behind-the-back pass from Paul Pierce, slammed in the dunk to give Boston a 36-point, third-quarter lead and then slashed his hand across his throat to signal what the Atlanta Hawks already knew.

"It's over," he said.

The game. The series. The surprising little scare Atlanta put into the NBA's best.

Garnett had 18 points and 11 rebounds, Pierce scored 22 points, and the Celtics turned back the pesky Hawks with a 99-65 victory today in Game 7 of their playoff series, earning a second-round matchup with LeBron James and the Cleveland Cavaliers.

Round 2 begins Tuesday night, and the Boston fans are ready.

"We want Cleveland!" they yelled as the Celtics bench nursed the game to its conclusion.

Rajon Rondo, who missed a potential game-tying 3-pointer in the Game 6 loss that forced the series back to Boston, had 10 points and six assists, taking his lumps in the game's pivotal play. Kendrick Perkins had 10 points and 10 rebounds before joining the rest of the starters on the bench in the formality of a fourth quarter, just as they did for much of the regular season.

Boston went 66-16 for the league's best record — 29 games better than the young Hawks team that earned the last playoff spot in the Eastern Conference. Although the upstarts put up little fight on the road, they won all three games in Atlanta by pushing back against Boston's Big Three of Pierce, Garnett and Ray Allen.

The skirmishes of the first six games boiled over with 9:09 left in the third quarter, with Boston already leading 51-28, when Rondo got the ball on a breakaway in the third quarter and had only Marvin Williams to beat.

The Hawks forward put an arm across his chest and took Rondo to the floor, where he lay for a few minutes while Celtics coaches and teammates checked on him. The officials immediately signaled a Flagrant 2 foul and, after reviewing the play, threw Williams out of the game.

The crowd was energized, and the Celtics were angry. Rondo hit both free throws, the Celtics got the ball and Allen, who hadn't made a basket since the first quarter, drained a 3-pointer to make it a 28-point game.

Then it was showtime.

The Celtics brought out some fakes and behind-the-back passes straight out of the Harlem Globetrotters. Rondo found Garnett underneath for an emphatic dunk — and the menacing gesture that will surely earn Garnett a fine from the league office — with 3:05 left in the third.

A minute later, he got his payback, knocking Zaza Pachulia to the floor on a backcourt pick. Celtics coach Doc Rivers, who earned his first playoff series coaching victory, took Garnett out of the game; he wasn't needed.

With 10:44 left in the game, Pierce and Rondo joined him on the bench. Pierce was the only Celtics starter to play more than 30 minutes. Sub Leon Powe was the third-leading scorer, with 12 points and four rebounds in 20 minutes.