Kevin Garnett scored 13 of his 23 points in the decisive third quarter and Paul Pierce added 22 as the host Boston Celtics beat the Detroit Pistons 101-90 Sunday night.

Ray Allen scored 13 points on just six shots and Rajon Rondo collected 14 assists for the Celtics (53-23), who had dropped four of six. They moved to three games behind idle Chicago in first place and remained one-half game back of Miami for second in the East.

More notably, Boston center Shaquille O’Neal, who had been out since Feb. 1 with an Achilles strain, returned and re-aggravated the injury less than a minute into the second quarter. He played 5½ minutes and made all three of his shots from the field but did not return.

Will Bynum scored 20 for Detroit (26-50), which has lost three straight and six of seven.

Despite shooting 62 percent (18 of 29) from the floor in the first half, Boston held only a slim 49-48 advantage at the break. The lead see-sawed the first four minutes of the third before the Celtics scored 13 straight points, getting five from Pierce, and four each from Garnett and Glen Davis to take an 80-64 cushion.

Detroit cut it to nine with 8½ minutes left, but Davis (11 points), Jeff Green and Ray Allen converted from the field to keep Boston clear.