Terry had some good looks. Barea not so much.
Barea had 3 gimme's and only made 1 of them. The rest of his shots were highly contested.
Terry had 6 relatively uncontested 3-pt shots(one was a 26-footer). So throw out the 26-foot three pointer, which was a poor shot and not a shot you expect to see him make, and Terry went 3-5 on his good looks from downtown. These are pretty much the shots you expect to see him make. Only one of his 3-pt attempts was contested well, and he missed it.
He had only 3 shots from 2-pt range. 2 of those shots were highly contested by Bosh and Haslem and were not good attempts. He had 1 shot in the PnR that was a gimme from 15 feet but missed.
All in all, he went 3-6 on shots you expect to see him make. He forced some shots, but that was mostly due to the shot clock. So when you break it down he didn't exactly have a bad shooting night. But those are shots he hit against the Lakers and Thunder, and when you take that away, the Mavs scoring takes a big hit.
Marion was big because he filled the void left by Barea and Peja's inability to score, but I still think Terry is the x-factor. I don't expect Barea to have a big series and i don't really know what to expect out of Peja, but if Terry isn't perfect with his open looks I don't think the Mavs have a chance in this series.