PHILADELPHIA — T.J. McConnell turned a surprise start into the save of the season and Dario Saric scored 25 points to help the Philadelphia 76ers stave off elimination in a 103-92 win over the Boston Celtics in Game 4 on Monday night.

The Sixers still face daunting odds headed into Game 5 and trailing 3-1 in the Eastern Conference semifinals: No NBA team has ever won a series down 3-0.

McConnell had a career-high 19 points, seven rebounds and five assists in only his second start of the season and meshed well in the backcourt with Ben Simmons. The crowd chanted “TJ! TJ!” each time he touched the ball in the fourth and proved why he has been so valuable even as bigger stars have sliced his playing time.

He was just what coach Brett Brown needed in a must-win game.

“I can tell you the Philadelphia 76ers spirit is just fine,” Brown said.

With NBA teams down 3-0 having lost all 129 series, the Sixers may need more than spirit to pull off this stunner.

Joel Embiid had 15 points and 13 rebounds and Simmons had 19 points and 13 boards.

Jayson Tatum led the Celtics with 20 points and Marcus Morris had 17.

The big 0 in the box score: Confetti pieces fired into the sky. The Sixers scrapped their traditional confetti cannon celebration after it was prematurely shot at the end of regulation in a Game 3 overtime loss.

The Sixers were in control in what could be their last home game of the season.

Boston’s Jaylen Brown and coach Brad Stevens were whistled for technicals late in the third and the Sixers capitalized with two free throws and an Embiid dunk that had rapper Meek Mill standing.

Embiid chirped at Marcus Morris and the Celtics forward flashed a “3-0” with his hands.

McConnell buried a 3 for a 14-point lead that would soon make that combination obsolete.

Brown was desperate to spark the Sixers and benched slumping forward Robert Covington (0 for 14 combined in Games 1 and 3) for McConnell.

McConnell, an undrafted third-year guard, had started 68 games combined over the last two seasons and served as an example of the type of player The Process was built on. He was an underdog, a hustler, a court general that made him a reliable favorite for Brown. But Simmons’ emergence put McConnell on the bench, and without complaint.

Cavs 128, Raptors 93

CLEVELAND — LeBron James sent Toronto into summer vacation for the third straight season as the Cleveland Cavaliers completed a series sweep of the Raptors with a 128-93 win in Game 4 on Monday night to advance to the Eastern Conference finals.

James finished with 29 points, 11 assists and spent some of the final 7:38 dancing near the bench during Cleveland’s 10th straight playoff win over Toronto, which changed its system, its roster and its approach but still can’t beat the game’s best player.

Kevin Love added 23 points and J.R. Smith 15 for the Cavs, who can now rest while waiting for the Boston-Philadelphia semifinal series to end.

Jonas Valanciunas scored 18 and Kyle Lowry had 10 assists to lead the exasperated Raptors. Toronto’s frustration hit its peak late in the third when All-Star DeMar DeRozan was ejected for a flagrant foul.