McCarthy is a master at piqueing your interest right from the opening line:
I sent one boy to the gaschamber at Hunstsville. One and only one. (p. 3)
This is an intro in first person pov from a sheriff. Within a page, we are switched to immediate action (not the usual McCarthy way) and introducted to Chigurh:
He dropped his cuffed hands over the deputy’s head and leaped into the air and slammed both knees against the back of the deputy’s neck and hauled back on the chain. (p. 5)
McCarthy’s way is graphic violence, but not usually quite so early on. We’re not quite sure yet if the "boy" in the first two pages is going to turn out to be Chigurh (which I’m pronouncing "Chigger") but we know that all characters tie in together eventually. What McCarthy just can’t leave be is timeline. He loves dropping us in the middle of something and often amid some unsavory characters and putting us at that disadvantage, we’re bound to his story to find out what’s going on.
Now that’s tension.