The 76ers outscored the Celtics, 31-17, in the fourth quarter and defeated Boston, 117-109, on Wednesday night at the Wells Fargo Center.

Joel Embiid scored 42 points, adding 10 rebounds. Here are three reasons the Sixers won:

Embiid’s recognition of the double team

Probably the biggest improvement of Embiid this season is being able to either pass out of the double team or shoot quickly enough against it. On this play, he is one-on-one with Tristan Thompson. When Payton Pritchard comes over and swipes at the ball, Embiid keeps control of it and makes a turnaround jumper.

A key stat in determining whether Embiid is doing well against the double team: He had just one turnover in nearly 33 minutes.

Second-half defense on Kemba Walker

The Celtics point guard was playing only his second game after missing the first 11 with a knee injury. In the first half, he was unstoppable, scoring 17 points and shooting 5-for-8 from the field, including 5-for-6 from three-point range.

During the second half, he scored on his first attempt, a driving layup, but then missed his final six shots and finished with 19 points. He was 0-for-3 in the second half from beyond the arc.

Walker was on a minutes restriction and played only 21 minutes and 43 seconds, including just 9:38 in the second half. He ended up shooting 6-for-15 from the field, including 5-for-9 from three-point range. Here is a look at all 15 field-goal attempts.

Walker appeared fatigued in the second half, but the Sixers were also doing a better job of helping on defense.

After scoring on a driving layup past Matisse Thybulle on his first shot of the second half, Walker then missed his final six shots. Thybulle was the defender for the first three shots, two three-pointers and a floater. Danny Green was on him when he missed a three, and then Walker had two drives to the basket that he missed while Ben Simmons was the primary defender.

Only two of his final six misses had no chance, a three that wasn’t close and the floater. Embiid altered a wild drive to the basket, while the other three were good shots that just didn’t fall.

Walker is quick enough to get by one defender, so help defense is critical in attempting to stop him.

Playing well in transition

The Sixers had 24 fast-break points. How about this play with Furkan Korkmaz scoring on a reverse dunk and drawing the foul after getting a nice feed from Simmons.

The Sixers owned a 7-0 advantage in fast-break points during the fourth quarter, and that was a key to their dominance over the final 12 minutes.