NFL vice president of officiating Dean Blandino affirmed the decision to not flag the Carolina Panthers for pass interference, a controversial decision at the end of the New England Patriots' 24-20 defeat Monday night, citing "proper mechanics" were used to make a "tight judgment call."

Tom Brady attempted to throw it to tight end Rob Gronkowski on the final play, but it was intercepted by Panthers safety Robert Lester

During the play, Gronkowski got held by middle linebacker Luke Kuechly and a flag was thrown. Then, referee Clete Blakeman announced there was no penalty on the play.

"The issue isn't the contact, the issue is the restriction and does it occur prior to the ball being touched," Blandino said on NFL Network. "At full speed the officials made a tight judgment call and they determined that the restriction occurred just as the ball was being touched [by Lester]. Again, at full speed you can see why they made that call."

Pass interference penalties aren't reviewable.

"Restriction occurred simultaneously with the ball being touched," Blandino said. "When you watch it at full speed you can see why they would make that call on the field."

Added Patriots coach Bill Belichick: "Whatever the officials think is the only thing that matters. They're the ones that make the calls. It's their explanation and their judgment that we all have to abide by."

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Aaron Wilson covers the Ravens for The Baltimore Sun.