Kemba Walker scored 15 shots in Boston’s Game 4 loss to Toronto on Saturday, taking only nine shots. Mark J. Terrill/Associated Press

As the Boston Celtics slogged through a 100-93 loss to the Toronto Raptors in Game 4 of the Eastern Conference semifinals, a few statistics stood out. The starters were 5 for 29 from deep, including abysmal 1-for-6 and 2-for-11 totals from Jayson Tatum and Jaylen Brown, respectively. The Raptors beat the Celtics 24-12 on second-chance points. Serge Ibaka was 4 for 4 from 3-point range.

But one statistic that might go a little under the radar: Kemba Walker took just nine field-goal attempts, finishing with 15 points on 4-for-9 shooting.

On an evening when everyone struggled immensely against Toronto’s defense, that number felt important, and Walker himself was upset with his performance.

“I’ve got to be more aggressive, I think,” Walker said. “I wasn’t aggressive enough. That’s unacceptable on my behalf, to be honest. There’s no way I can just be taking nine shots. That’s unacceptable.”

The Raptors’ defense was stifling on both Walker and Tatum, aided by the cold shooting night from the rest of the team. At moments in the second half, Toronto ran a box-and-one on Tatum, and their zone worked hard to keep Celtics players away from the paint.

That zone – and Toronto’s focus on keeping the Celtics from scoring in the paint – helped stymie Walker. He took just three shots inside the arc and made all three, but the Raptors effectively discouraged any further forays inside.

Celtics Coach Brad Stevens seemed to deflect a bit when asked about Walker’s field-goal attempts, and whether they needed to focus on getting him more shots.

“We weren’t very crisp all night,” Stevens said. “Once we missed a few, we started trying to hit home runs. We need to definitely (avoid) that, that’s for sure.”

The Celtics know they have a lot of work ahead of them. At one point, Walker said the Celtics didn’t match Toronto’s intensity.

“It’s tough, man,” Walker said. “Obviously we didn’t want to come out that way, but it just happened. We’ve just got to clean it up. We’ve got to find a way, man. We’ve got to be better. I have to be better. I have to find a way to get my teammates at a higher intensity, and I will. I’m going to try my best to bring the best out of these guys. Nobody ever said it was going to be easy. We know how the playoffs is, and these are the defending champs. These guys have been through it. These guys have been through it. They’ve been through the fight before. They’ve been down before. They know what it takes. But I can’t stress enough how much we just have to be better.”