The Celtics’ Kevin Garnett, who finished with 20 points, strips the ball from the Hawks’ Josh Smith during the first half of last night’s Game Four at Philips Arena in Atlanta.

The Providence Journal / Glenn Osmundson

ATLANTA — Kevin Garnett. Paul Pierce. Ray Allen. How about Joe Johnson?

Forget the Celtics’ Big Three stars. Johnson, a one-time Boston first-round draft pick, has stolen the show in the last two games of a first-round playoff series that now appears to be up for grabs.

Johnson poured in 20 of his game-high 35 points in the fourth quarter to help wipe out a 10-point Celtics lead and rally the Atlanta Hawks to a 97-92 win last night at Philips Arena. The Hawks now have tied the series at two games apiece with Game Five set for tomorrow in Boston and Game Six coming back to the Peach State Friday night.

Johnson’s heroics stunned a Celtics team that seemingly had the game, and the series, by the throat. Up, 75-65, after three quarters, the Celtics hit only one of their first 10 shots in the fourth and lost control. Johnson continually beat Ray Allen off the dribble or thanks to high-ball screens by Mike Bibby.

“We have been down before but we knew we could play with the Celtics,” said Johnson. “We started the game slow and they hit us in the mouth, but we withstood it and made a run. We knew we had a chance to come back, and we jumped on it in the fourth quarter.”

Johnson made 7-of-10 shots in the quarter, including two 3-pointers. He also made 4-of-5 free throws.

“Joe Johnson willed us to win,” said Hawks’ coach Mike Woodson. “He was hot and we continued to get him the ball. It was nice to see.”

For the second straight game, Johnson received a nice assist from Josh Smith. Matching up against Garnett, Smith poured home 28 points and blocked seven shots. Bibby added 18 points, all in the first half.

Allen led the Celtics with 21 points, Garnett added 20 and Pierce scored 18, but the trio combined to shoot 4 of 11 for 11 points with the game on the line in the fourth quarter.

“I thought we got really good shots down the stretch,” said Pierce. “We were able to get the ball down low and we got looks we’re able to make. But that’s the breaks of the game. You have to live with it and be able to bounce back.”

Allen said he “was always trailing,” Johnson in the final period on defense and obviously didn’t get enough help. Pierce tipped his hat to Johnson, saying, “You want to get the ball out of his hands when he gets hot. We did a good job of crowding him, but he was able to get in the lane. Joe Johnson is an all-star. He’s a proven player.”

The final 12 minutes depressed the Celts because they put together a very strong effort up until that point. Pierce came out clearly fired up, as did the entire Celtics team as Boston shot out to a 16-3 lead after making six of its first seven shots. The defense was spectacular as the Hawks missed their first four shots and threw the ball away three times. Pierce and Ray Allen each canned two 3-pointers in the opening run.

But the Hawks quickly counter-punched. A big assist came from mounting foul calls on the Celts as Pierce, Garnett and Rajon Rondo ended the opening 12 minutes with two fouls apiece. The Hawks caught the Celtics late with an 11-1 run to close out the quarter with a 29-24 lead.

The game’s fireworks only heated up in the second quarter. With Atlanta leading, 37-29, and 7:24 to play, Garnett was called for a foul when he stuck an elbow into ZaZa Pachulia’s chest. Pachulia took exception, got up into Garnett’s face and nearly head-butted the Celtics’ star. Players from both teams converged on the scene with Boston’s Sam Cassell shoving Johnson, who didn’t back away. Woodson sprinted onto the floor as a peacemaker and when order was restored, the officials had slapped technical fouls on Garnett (his third foul), Pachulia, Cassell and Johnson.

The Celtics responded well to the fracas and nearly wiped out the Hawks’ lead to trail by only 51-48 at halftime. The Celts appeared to have the game in control after an outstanding defensive third quarter where the Hawks were outscored, 27-14, and shot 35 percent. Johnson made just 1-of-4 shots in the period while Garnett had nine points and Boston carried a 75-65 lead into the fourth quarter.

But that’s when Johnson caught fire and the Celts went cold.

Boston snapped a 1-for-11 shooting skid with a Garnett jump hook that made it 86-82, but they simply could not stop Johnson. He skipped by Allen and Rondo for a lane drive, scored on another drive, hit two free throws and then made two more to make it, 95-89, with 14 seconds left. A James Posey 3-pointer cut the lead to 95-92 but free throws by Smith with 2.6 seconds left sealed the victory.

kmcnamar@projo.com