CLEVELAND - Back to even, and back to Boston - with authority.

LeBron James scored 21 points, jamming in a dunk over a defenseless Kevin Garnett in the final 2 minutes as the Cleveland Cavaliers beat the homesick Celtics 88-77 in Game 4 on Monday night to tie their best-of-seven Eastern Conference semifinal series at 2.

Still stuck in a shooting slump, James dominated down the stretch and finished with 13 assists - four in the fourth quarter. The Cavaliers, whose defense has been overlooked, held the Celtics to just 12 points in the final period.

Boston dropped to 0-5 on the road in the postseason, a stunning slip for a team that went 31-10 on the road during the regular season. During their visit to Ohio, the Celtics lost their momentum in the series but will now head home, where they went 35-6 before the playoffs started.

Game 5 is Wednesday night, and Game 6 will be back in Cleveland on Friday.

James was just 7-for-20 from the floor, but he did everything else for the Cavs. In the final 8:45, he had four assists, a 3-pointer and a dunk.

With the Cavs leading 82-75, James drove past Paul Pierce on a screen near the foul line, head faked past James Posey and then dunked on Garnett.

Although James is shooting only 26 percent (20-of-78) from the floor, the only numbers the Cavs care about are the pair of 2s that show this series is as tight as possible.

Garnett scored 15 points but only two in the second half as Cavs forward Anderson Varejao harassed the All-Star all night. Ray Allen had 15 points and Paul Pierce 13, but the Celtics’ stars were only a combined 16-of-40.

James missed his first six shots in the fourth before draining a 3-pointer in front of Boston’s bench with 3:17 remaining to give the Cavs a 79-73 lead.

After a bucket by Pierce, James dished to Daniel Gibson for a 3-pointer as the Cavs opened a seven-point lead.

One time James got loose on a fastbreak, and Pierce wrapped his arms around him to prevent a possible dunk.

The players’ momentum carried them into a crowded front row, where James’ mother, Gloria, tried to help her son by grabbing at Pierce. James yelled at her to sit down.

James made both free throws to give Cleveland a 41-33 lead, but seconds later, he picked up his third foul and had to come out. With James on the bench, the Celtics pounced and scored eight straight to tie it before the Cavs went to the locker room up 45-43 at half.

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