To make Celtics better, Kemba Walker believes he must be better

While Gordon Hayward (25 points) and Jaylen Brown (24 points) turned in good offensive performances, Kemba Walker (far right) was disappointed in his play — scoring 19 points on just 7-of-19 shooting.Celtics point guard Kemba Walker knows he has to be better.

“I’m more upset about my individual play than anything right now,’’ Walker said Wednesday night after his team’s uninspiring 116-103 loss to the Detroit Pistons. “It starts with me. I have to be better for my teammates.’’

Walker shot just 36.8 percent from the field against Detroit, knocking down 7 of 19 field-goal attempts. Nine of his misses came from behind the arc, as he connected on only 2 of 11 three-point attempts. The Celtics…