DENVER — Putrid. Gross. Unwatchable.

Those are a few of the words that could describe the Denver Broncos’ offense in the first half.

At the break, Denver had 112 net offensive yards. But that number is even generous.

“It wasn’t good,” head coach Vance Joseph frankly said after the game. “Offensively, our first three or four drives were three-and-out. They played good football in the first half, and we didn’t.”

The Broncos racked up 20 of the 112 yards on the last play of the half when the Oakland Raiders were playing prevent defense, essentially allowing Denver to get those yards.

Take that away, and the team had less than 100 yards of offense in the first half.

“We were just a tick off in the first half,” Case Keenum said, making the zero total first half points not appear as bad. “I think there were at least two first downs where we were almost within a yard of converting. Had a great play call and they just made a tackle, made a play. Little things like that make a difference.”

Additionally, nearly half of those 112 first-half yards came on a 53-yard scamper by Phillip Lindsay in the second quarter. That play was negated by a Keenum interception just three plays later.

“They were playing a bunch of shell coverage — Cover 2 and Cover 4. Our thought was to run the football, but we couldn’t do it,” Joseph said, breaking down Denver’s first half gameplan. “They were playing really stout up front, and again, that defense played good football for them today.”

On top of only one third-down conversion and 33 net passing yards, Denver had more punts and penalties (four) than first downs (three) in the first half.

“Going three-and-out those first couple of times was tough,” Keenum said, speaking the truth. “Just couldn’t get anything going.”

It was all too reminiscent of last year’s offense and all of the woes that came with it.

But as the hottest home game in Broncos’ history moved closer to the evening, Case Keenum and Co. heated up as the temperates slightly cooled.

“We came in and said, ‘The flood gates are about to open,’” Keenum said, explaining the mentality entering the second half. “We just needed one little play, one little thing to get it going and we got it going.”

In the first half, the Broncos’ drive chart didn’t look pretty: Punt, punt, punt, interception, punt, end of half.

Offensive coordinator Bill Musgrave — who both Derek Carr and Case Keenum called a genius in the lead up to Week 2 — nearly flipped that script on its head in the second half.

Denver’s drive chart in the second half was exclusively scoring drives: Touchdown, field goal, touchdown, field goal.

“We got some runs, so it forced them to play more single high, and when they played shell and played Cover 2, we went more vertical down the field. Our plan kind of changed,” Joseph explained the change after the game. “We became more aggressive versus the zones.”

Denver’s more aggressive plan led to 20 points in the final two quarters to give them the 20-19 victory and move them to 2-0 on the season.

In the second half, Denver over doubled their first-half production, putting up 273 yards of offense by way of 89 on the ground and an impressive 184 in the air.

Denver had 17 first downs and seven third-down conversions all in the second half.

“In the second half, we thought, offensively, we had to be more aggressive, take more shots down field, and that made them a little soft in the second half,” Joseph stated. “Our guys kept fighting, kept playing — played through adversity and won a football game.”

Along with being more aggressive, Musgrave turned to the no huddle, hurry-up offense to get the team in a groove.

“I love going fast break,” Keenum said with enthusiasm in his voice. “Kind of brings me back to my roots, going back to Houston — I don’t think we ever huddled. But it’s good. It’s a good change of tempo… I thought it was a good mix up today.”

A good and needed mix up, indeed.

Musgrave also threw in a Wildcat formation, led by Lindsay, and a Keenum quarterback draw for a touchdown on 4th-and-one from the goal line.

“You get one first down, and it leads to more,” Keenum said, after putting together 17 first downs in the second half. “That’s what happened in the second half. Just little things.”

On the offensive side of the ball, Sunday was a tale of two halves, or perhaps two seasons.

The drastic differences from the first and second half show the Broncos’ winning formula on the offensive side of the ball: Play fast and aggressive.