LOS ANGELES -- After the worst offensive first half in the franchise's playoff history, coach Jason Kidd's primary concern wasn't the Dallas Mavericks' poor shooting. He called out his team for allowing the LA Clippers to dominate them physically.

"They were physical and we were passive," Kidd said after the Mavs' 109-97 loss in the opener of their first-round playoff series, a game in which they trailed 56-30 at halftime.

With Clippers star Kawhi Leonard sidelined due to right knee inflammation, Los Angeles' James Harden scored 20 of his 28 points in the first half, doing the bulk of his scoring from 3-point range. The tone, however, was set by Clippers center Ivica Zubac bullying the Mavs in the block.

Zubac scored 10 of his playoff career-high 20 points in the first quarter, beginning with a pair of post-ups when he backed down Dallas center Daniel Gafford. The Clippers had a 24-8 advantage in points in the paint by halftime.

"I just didn't come out ready to play, in all honesty," said Gafford, who got in early foul trouble and finished with 3 points and no rebounds in 14 minutes. "I have to be better when it comes to me being a starter on the floor. I have to be able to be better in areas that I've always succeeded in throughout the regular season. I got to come out and I got to play playoff basketball, not what I showed out tonight."

Kidd was encouraged by the Mavs' response after halftime, but Dallas had dug too deep a hole to mount a serious comeback attempt. The Clippers maintained a double-digit lead for the final 36 minutes, 39 seconds.

"It really centered around the foundational point of talking about physicality and this being the playoffs," Mavs guard Kyrie Irving said. "A lot of guys aren't used to being here. A few young guys aren't used to being here, so they don't know what they can get away with and what the refs are going to call. I think this was a great first test for us. We obviously failed and we came out with a loss, but I think there are some things we can take into Game 2."

Dallas was held to only 8 points in the second quarter, the Mavs' lowest-scoring quarter this season, according to ESPN Stats & Information.

Mavs stars Luka Doncic and Irving finished with 33 and 31 points, respectively, but they combined for only 17 points on 5-of-19 shooting in the first half.

"I just got to stay aggressive," Doncic said. "That was my bad in the first half. I wasn't aggressive enough."