The Denver defense forced a three-and-out on the first possession of the game, as linebacker Von Miller and defensive tackle Kevin Vickerson stopped Bucs running back Doug Martin on second and third down to bring up a fourth-and-1.
Wide receiver Trindon Holliday returned the punt 17 yards to set the Broncos offense up at their own 35-yard line.
Quarterback Peyton Manning completed passes of 10 and 12 yards to tight end Jacob Tamme and wide receiver Eric Decker to move Denver to the Tampa Bay 25.
Two plays later, a defensive pass interference penalty on a pass attempt from Manning to Matthew Willis moved the chains on third-and-8 and put the Broncos in the red zone.
Running back Knowshon Moreno then got the Broncos down to the 1-yard line with a 12-yard burst.
On first-and-goal from the 1, defensive tackle Mitch Unrein lined up as an eligible receiver at the tight end position. Manning faked the hand off to Moreno and found a wide open Unrein in the end zone to put the Broncos ahead early.
Unrein was an asset near the goal line earlier in the season for the Broncos, leading running back Willis McGahee into the end zone from the fullback position against the Saints. This time, he got a new opportunity as the tackle made his first career reception and touchdown.
Matt Prater converted on the extra point to put Denver up 7-0 with 8:53 remaining in the first quarter.
Listen to the audio highlight of the touchdown here and watch the play here.