San Diego Chargers at Denver Broncos -- Week 11

Where: Sports Authority Field at Mile High, Denver (grass, outdoors)

When: Sunday, 4:25 p.m. EST (CBS)

Spread: Broncos by 7.5

Forecast: Mostly sunny, 59-62 degrees.

2012 records: Broncos (6-3); Chargers (4-5)

Past results: Two most recent meetings -- Nov. 27, 2011: Broncos 16, Chargers 13. (OT); Oct. 15, 2012: Broncos 35, Chargers 24. Series record: Broncos hold a 56-48-1 edge.

What matters: When the Broncos trudged to the locker room at halftime of their Oct. 15 game in San Diego, their current status as Super Bowl contenders seemed a faint dream. They trailed the Chargers 24-0, were staring at a two-game deficit in the division, and had spent the previous 30 minutes stumbling and bobbling their way into a hole that seemed too deep to climb from. But a quick start to the second half via a Peyton Manning-to-Demaryius Thomas touchdown pass and a Philip Rivers fumble that CB Tony Carter returned for a touchdown changed everything, and neither team has been the same since. The Broncos haven't lost, and the Chargers' sole win since then came over the woeful Chiefs.

Rivers hasn't been bad since halftime of the Broncos' comeback win; he threw three interceptions and was sacked four times in that fateful second half -- the same numbers as he has incurred in the last three games. But an errant fourth-quarter pass at Tampa Bay last week that was returned for a touchdown brought Rivers back to the same point as he was on Oct. 15 -- someone who's still capable of shredding a defense but under pressure to carry the team by himself, which can lead to mistakes that sink the Chargers' chances. If the Broncos crank up the pressure again, Rivers will find himself in the same spot Sunday.

Sunday is basically the Chargers' last stand in the AFC West race -- and perhaps also the last stand of coach Norv Turner and general manager A.J. Smith, who are likely both on the firing line if they miss the playoffs for a third consecutive season. For the Broncos, it's a chance to bury their long-time nemesis and move on to bigger goals.

Who matters: Broncos CB Champ Bailey kept San Diego WR Malcom Floyd under wraps last month, but in the last two weeks Danario Alexander has emerged as the Chargers' deep go-to threat, catching 11 passes for 195 yards, including an 80-yard touchdown last week. He gives Denver's cornerbacks another foe to consider, and if Rivers can find Alexander for a big play early, Denver's other cornerbacks (Chris Harris and Tony Carter) might have to temper their aggression.

Denver successfully exploited the Chargers' issues at tackle last month, and with LT Jared Gaither not expected to play after missing all week because of a groin injury, look for the Broncos to try to exploit LT Mike Harris and RT Jeromey Clary by moving their edge pass rushers around. The Broncos might be without DE Elvis Dumervil (left shoulder strain), but fill-in Robert Ayers played well last week, notching a sack and two tackles for losses. If Ayers and Von Miller can generate the same pressure on Rivers that Miller and Dumervil did last month, then the 30-year-old quarterback will make mistakes.

Key matchup: Whether the Broncos have used safeties, linebackers or the slot cornerback, nothing has helped them improve their play against tight ends. The Broncos allowed 100-yard games to Cincinnati's Jermaine Gresham and Carolina's Greg Olsen the last two weeks, and tight ends have accounted for five of the last nine touchdowns allowed by the Broncos since Week 6. Two of those were by San Diego's Antonio Gates on Oct. 15.

"Here comes the best in the game coming up this week," Bailey said.

The return of LB D.J. Williams to the Broncos' defense could help, but the Broncos aren't expected to use him extensively after he missed the last nine games because of suspensions.

Injuries of note: Dumervil is questionable; he practiced on a limited basis Friday after being out the previous two days because of a left shoulder strain. RG Chris Kuper is doubtful after missing last week with a sprained left ankle; he practiced on a limited basis all week. CB Tracy Porter was ruled out for a fifth consecutive game after not practicing all week.

Inside stuff: RB Willis McGahee isn't under pressure yet, but his career-high five fumbles -- including two last week -- have the Broncos concerned. They spent extra time this week working on football-protection drills to try to cure McGahee of the recurring problem. The Broncos don't have a viable every-down option behind him; rookie Ronnie Hillman hasn't proven he can go between the tackles effectively, Lance Ball is more of a special-teamer and Knowshon Moreno is so far in the doghouse that he's been inactive for seven consecutive games after fumbling in Atlanta in Week 2.

Connections: Royal and TE Dante Rosario left Denver for San Diego as free agents this past offseason. Rosario spent only the 2011 season in Denver; Royal was a 2008 second-round pick who played four seasons there … Broncos CB Porter and Chargers DT Aubrayo Franklin were teammates in New Orleans last year.

Stat you should know: Denver's second-half scoring margin (plus-111) is 140 points better than its first-half margin, the highest positive discrepancy in the league. San Diego's second-half scoring margin (minus-35) is 88 points worse than its first-half margin; that's the worst second-half falloff in the league.

Record watch: With one more touchdown pass, Manning will pass Dan Marino to take sole possession of second place all-time in league history with 421. Manning can also tie John Elway for the second-most wins all-time by a starting quarterback (148) if the Broncos win. Looking ahead: If the Broncos complete a sweep of the Chargers, their focus will turn toward trying to earn a first-round bye, since the Chargers would have to finish four full games better than the Broncos in the final six weeks in order to win the division. Even if Denver loses Sunday, its chances of out-racing the Chargers would still be good; the Broncos' last six games include a trip to 3-6 Oakland, a home game against the 2-7 Browns and a home-and-home against the dreadful Chiefs.

Prediction: Broncos 31, Chargers 24.

For up-to-the-minute Broncos updates, follow Andrew Mason on Twitter at @CBSBroncos.