I did not think going with a 30 front would work, but thanks to amazing effort by the from three, they did get enough pressure especially in Slovis's face that made him uncomfortable.
Next they played zone under and clogged up the middle which is why BYU had 3 picks which all came in the middle of the field. The defense kind of gave up passes in the flats and on the short out routes, but then would roll man coverage on occasion which caused Slovis to throw over the middle. And I think BYU dropped 2 more potential INT's
BYU also dared USC to run by only putting 5 in the box. USC took some advantage of this, BUT BYU would sometimes walk up a sixth man and they were able to get stops at critical times.
Ultimately they gambled that Slovis would not be very good at getting deep into his read progressions because of his lack of experience.
It was a masterful gameplan. Tuiaki has a very different approach than Bronco, but it was effective Saturday.