The Drew Lock era will likely begin this week at home against the Chargers, finally giving the Broncos a sense of optimism, especially around the quarterback position and the offense as a whole.

Let’s take a look at what must happen for the Broncos to turn that optimism into a winning result on Sunday.

Quarterback enigmas on either side

As is normally the case, the quarterback will be the key determining factor for both teams on Sunday. However, less normally, both are also shrouded in mystery.

Philip Rivers appears to be at the end of his rope. The veteran passer has posted a passer rating of 85.5 this season, his worst mark since 2007, and a QBR of 47.1, the second-lowest mark of his entire career (42.6). His touchdown-to-interception ratio is also a dismal 15:14, which is the worst of his career by a healthy margin. Can the Broncos defense stifle Rivers one last time before he retires?

On the other hand, the Broncos will likely be giving Lock his first career start, which is a completely different enigma. Does Lock come out red-hot as a rookie like Baker Mayfield did, or does he look like a complete disaster a la Paxton Lynch? The answer should decide Denver’s fate Sunday.

Stopping Ekeler and Gordon

In order to complete the season sweep of the Chargers, the Broncos must shut down their backs Melvin Gordon and Austin Ekeler.

The duo has already gained more than 1,500 yards and 14 touchdowns combined, making them 37.8 percent of the Chargers’ total offensive production in yards and 64.6 percent of their total offensive production in terms of touchdowns.

Without a doubt, the Chargers’ backfield is the lifeblood of their offense. In wins this season, the unit averaged 133.5 yards of total offense. In the Broncos victory from earlier this season over the Chargers, Denver’s run defense did an excellent job on the ground, holding them to 38 yards.

However, they were still able to attack the Broncos through the air, where the backs gained 93 of the team’s 243 yards. Denver must be better about stopping that this time around.

Turnovers and Takeaways

The turnover battle will decide this game for the winner.

The Chargers have been one of the league’s most turnover-happy teams this season. They’ve given the ball away in all but two of their 11 games, and they’ve turned the ball over multiple times in six of those games.

The Bolts’ turnover situation has only gotten worse as the season has worn on. In their last two games, the Chargers have turned the ball over seven times, and they’ve turned the ball over at least three times in four of their last seven games.

The Broncos’ defense is on the opposite side of the spectrum, unable to force takeaways.

Denver’s defense has forced a turnover in just five games this season and has forced multiple turnovers just three times this season. In those three games, Denver is 2-1 and has outscored opponents 59-40, with their one loss coming in improbable fashion to the Vikings.

The first time these teams matched up this season, the Broncos forced three turnovers. Can they do it again?