ENGLEWOOD, Colo. -- Through all of the frustrations, offensive woes and crushed preseason expectations the Denver Broncos have had to wrestle with thus far, their defense has been the one thing they could cling to. They entered Sunday’s game against the Las Vegas Raiders as the league’s top scoring defense and among the league's top three in virtually every major category.

“We all know things work out way better when you’re winning,’’ safety Justin Simmons said.

And, yes, the Broncos offense didn’t top 16 points again Sunday, and yes, the Broncos botched a few more scoring opportunities, and yes, even a change at play-caller -- quarterbacks coach/passing game coordinator Klint Kubiak called plays instead of coach Nathaniel Hackett -- didn't help cure many of their ills. But in a season with almost no margin for error, the Broncos defense has finally cracked in consecutive weeks with a game on the line.

Derek Carr’s 35-yard touchdown pass to Davante Adams with 8:24 left in overtime closed out the Broncos’ seventh loss of the season, 22-16. And while Denver’s offense continued to struggle, the Broncos’ defense couldn’t close the deal in the final minutes of regulation, and a botched coverage assignment resulted in the game-winning touchdown in overtime.

On what turned out to be the game-winner, the Raiders put Adams in the slot, next to wide Mack Hollins on the right side of the formation. At the snap, Hollins drove down inside to cross the field and as the Broncos’ defensive backs, including Pat Surtain II followed him, both with their eyes and intentions, Adams roamed free up the field as Raiders running back Josh Jacobs signaled the touchdown as the ball left Carr’s hand.

“[Adams] went on a double move,’’ Surtain said. “[I] should have kept my leverage, but [I] have to correct that.’’

“I’m not trying to be rude or anything, but I know how it can be ... it’s not his fault,’’ Simmons said. “This game is not on one guy, ever. There are 11 guys out there on the field, and we all have a responsibility, especially in overtime, to make a play, get off the field, and give our offense a chance to win the game -- that’s first and foremost.’’

The Broncos’ offense and special teams made several mistakes Sunday, including Melvin Gordon III’s fumble at the Raiders' 2-yard line. Gordon was waived by the team Monday. A blocked 25-yard field goal and Russell Wilson’s decision to throw an incompletion instead of hold the ball just inside the two-minute warning in regulation were also among the issues, but another big concern at the moment might be the Broncos' defense looking wobbly.

The numbers are still good (No. 3 in scoring defense, No. 3 in total defense and No. 1 in red zone defense), but in back-to-back one-score losses, the group couldn't close out.

“We just need to finish games. It’s that plain and simple,’’ linebacker Josey Jewell said. “We do well in the first quarter, second quarter, third, and we just need to keep that throughout the fourth quarter. Stay consistent in this game, and we don’t even need to bring it to overtime.’’

The Broncos surrendered a 63-yard touchdown pass on a flea flicker late in the third quarter against the Titans last week, and surrendered a 10-play field-goal drive in the closing minutes of the game to let a 10-7 lead turn into a 17-10 loss.

Sunday, they led the Raiders 16-13 with 3:30 to play in regulation. Carr then hit 21- and 43-yard passes on back-to-back plays in what became a seven-play drive to tie the game.

And while the Broncos’ league-worst scoring offense (14.7 PPG) has done the team’s defense few favors, the lack of drive-snuffing sacks, tipped passes and lock-down plays late in games over the last two weeks for the defense has now raised a new concern for a team that already has plenty.

“At the end of the day, it’s just poor execution,’’ Simmons said. “That’s what I’m saying, everybody keeps talking about, defense this, defense that. You talk about ratings and all this other stuff that doesn’t matter. What matters is how you execute when it matters most. Had the defense been able to get a stop in a two-minute situation and get a fourth down, stop offense on the field, we win the game, point blank, period."