Playing their best game of the year, the Jaguars got superb performances from quarterback David Garrard (25-for-34, 276 yards) and tailback Maurice Jones-Drew (125 yards, two TDs), plus three takeaways from their defense in a cold, misty win.
Garrard threw one TD and no interceptions.
The Jaguars (3-3) took the second-half kickoff and covered 80 yards in just three plays, with Jones-Drew bolting up the middle for a 46-yard touchdown that put Denver in a 17-7 hole.
After the Broncos settled for Matt Prater's 39-yard field goal, Jacksonville scored again, on Marcedes Lewis' 30-yard TD catch.
The Broncos were without three offensive playmakers in rookie receiver Eddie Royal (ankle), former Western Michigan tight end Tony Scheffler (groin) and tailback Selvin Young (groin), and they lost slot receiver Brandon Stokley to a head injury shortly after his 11-yard touchdown catch that capped Denver's first drive.