LeBron James put his mom and then the Boston Celtics in their places.

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

Still stuck in a shooting slump, James dominated down the stretch and finished with 13 assists—four in the fourth quarter. The Cavaliers, too, showed that they can play stingy defense, holding the Celtics—the NBA’s best defensive team—to just 12 points in the final period.

“That’s what we needed to do,” said James, whose mother, Gloria, came to her son’s defense in the first quarter after he got tangled with Paul Pierce and Garnett.

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