Bortles' legs once again proved to be the difference in the second half, as the QB ran for 36 yards and capped off a 15-play 86-yard drive with a TD to tight end Ben Koyack to give the Jags a 10-3 lead.
Brees, who completed 23 of 32 passes, threw first-half touchdown passes of 80 yards to Ted Ginn Jr. and 9 yards to Josh Hill. Fullback Zach line and running back Alvin Kamara each ran for short touchdowns, the latter set up by Michael Thomas 46-yard reception.
Bills fans are such a force in Jacksonville Sunday that Jaguars fans are taking lessons on tailgating from them.
After the Bills offense had to settle for a field goal following a first-and-goal series that began at the one-yard line, Buffalo barely crossed midfield the rest of the game.
In the postseason for the first time since January 2008, the third-seeded Jaguars (11-6) advanced to play at No. 2 seed Pittsburgh next week.More news: SpaceX successfully launches top-secret Zuma spacecraft
Thousands of Buffalo Bills fans have escaped sub-zero temperatures and invaded Jacksonville this weekend expecting to make the most out of the first playoff appearance in 17 years.
Bortles was a big reason Jacksonville won the game and a big reason it was so close.
The Bills finished with 263 yards, with 119 of those coming from hobbled running back LeSean McCoy (ankle).
A last-ditch drive by the Bills with 1:51 remaining only got as far as midfield as Nathan Peterman, on in relief of an injured Tyrod Taylor, was intercepted on a 2-and-20 play from the Bills 48-yard line. At the tail end of the magnificent run, he put lockdown cornerback Jalen Ramsey, who is a solid tackler, in a blender.