Their 10-point lead felt as sturdy as a sandcastle when the Broncos’ offense was gifted a gimme in the third quarter Sunday afternoon. Safety T.J. Ward picked off a Philip Rivers pass and returned it to the San Diego 7-yard-line. Just seven yards between the Broncos and a seemingly insurmountable three-score lead.

Denver’s defense put a beach ball on a tee and the Broncos’ offense whiffed. Two plays later, rookie Devontae Booker fumbled at the 2-yard-line. San Diego then marched 98 yards for a touchdown.

In their first game without starting running back C.J. Anderson — lost for the regular season with a torn meniscus in his left knee — the Broncos’ offense sputtered. Denver rushed for just 57 yards.

“We still have to get better as a unit,” said running back Juwan Thompson, who was signed off Denver’s practice squad last week and scored on his only carry, a 1-yard plunge. “If one guy goes down, we have to make sure the team doesn’t go down. But we have to keep pushing to figure out where our flaws are.”

The Broncos’ run game is stammering. And, two days before the NFL’s trade deadline, their depth seems thin. Booker injured his shoulder on the Broncos’ first drive before returning later in the quarter. Kapri Bibbs, who took his place, fumbled on his first carry.

“We try to continue to have trust in them and trust that they’re going to finish the game and do their job,” Broncos cornerback Chris Harris said. “It’s tough sometimes. That’s what, for me, the leaders on this team, we have to keep everybody calm whenever something on the other side of the ball goes wrong.”

Thompson maximized his field time. In one carry, he scored a one-yard touchdown, a pushing battle up the middle in the fourth quarter that finally gave the Broncos some breathing room and a 24-13 lead. His score capped the Broncos’ best offensive output, a 13-play, 75-yard drive that ate 6 minutes and 30 seconds.

The Broncos rushed seven times on that drive for 32 yards. But more importantly, it finally gave Denver’s defense a breather. And a sliver of confidence in their offensive counterparts. Related Articles October 30, 2016 Defense’s big plays key Denver Broncos’ victory over San Diego Chargers

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Bradley Roby’s 49-yard interception return for a touchdown gave the Broncos their first lead, in the second quarter, the team’s only touchdown in the first half. Denver’s defense picked off three passes. But the offense turned it into only one touchdown, a two-play, 10-yard drive that led to Booker’s 3-yard touchdown run in the third quarter.

“When the defense gives us a turnover, we have to score,” Thompson said. “There are no ifs, ands or buts. We have to find a way to get a touchdown or get three points.”

Chargers running back Melvin Gordon, on the flip side, kept his team churning. He ran for 111 yards on 23 carries, and caught four passes for 44 yards. As the Chargers drove 98 yards in the third quarter after Booker’s fumble, with 13 plays over 7 minutes and 42 seconds, Gordon got seven carries for 31 yards. And San Diego got within four points in a game Denver was ready to all but put out of reach.

The Broncos, meanwhile, never hit stride. They rushed just seven times in the first half. Booker finished with 19 carries for 54 yards and a fumble. Kapri Bibbs added four yards on two carries. Thompson added a yard and Trevor Siemian lost two yards. They totaled 57 yards rushing — less than half the Chargers’ total of 123.

“C.J. is out. We have to get used to that feeling,” Bibbs said. “Of course we have to be ready for next week. We have to get better and better.”