San Diego Chargers strong safety Marcus Gilchrist (38) celebrates after sacking Denver Broncos quarterback Peyton Manning (18) in the second quarter of an NFL football game, Thursday, Dec. 12, 2013, in Denver. San Diego Chargers wide receiver Keenan Allen (13) is congratulated by teammates after catching a touchdown pass against the Denver Broncos in the second quarter of an NFL football game, Thursday, Dec. 12, 2013, in Denver. Denver Broncos quarterback Peyton Manning (18) pounds his fist on the ground after throwing an interception against the San Diego Chargers in the fourth quarter of an NFL football game, Thursday, Dec. 12, 2013, in Denver. San Diego won 27-20. Denver Broncos quarterback Peyton Manning (18) greets San Diego Chargers coach Mike McCoy at midfield after the Chargers beat the Broncos 27-20 in an NFL football game, Thursday, Dec. 12, 2013, in Denver. AP Photo/Joe Mahoney San Diego Chargers running back Ryan Mathews (24) gets past the Denver Broncos defense in the fourth quarter of an NFL football game, Thursday, Dec. 12, 2013, in Denver. DENVER (AP) - Now, Peyton Manning gets a chance to rest. Big question: Does he really need a break? Philip Rivers and the San Diego Chargers kept Manning on the sideline most of the game and handed the Denver Broncos and unexpected and harmful 27-20 loss Thursday night. Rivers threw two touchdown passes to Keenan Allen and kept the Chargers' offense on the field for nearly 39 minutes, keeping their playoff hopes alive while turning Denver's supposedly easy road to the AFC West title and top seeding in the conference into something much different. "We didn't play well, didn't stay on the field, didn't have the ball much and, when we did, we didn't do much with it," Manning said. The Broncos gained 13 yards on the 13 plays they ran after taking a 10-3 lead late in the first quarter. That covered four drives during which they went three-and-out three times and picked up a total of one first down. "The longer you keep the ball and the less he has it, the better off you're going to be," said Chargers coach Mike McCoy, Manning's former offensive coordinator. Rivers finished 12 for 20 for 166 yards and improved to 28-6 in December. Ryan Matthews matched his season high with 127 yards on 29 carries. After Denver's long dry spell on offense, San Diego led 24-10, and though the Broncos (11-3) had overcome double-digit deficits four times this season to win, it wasn't happening this time. They pulled within seven and Manning got the ball on the Denver 3 with 5:50 left. He moved the Broncos 30 yards in two plays with the help of a penalty. But the Chargers' maligned defense produced some pass rush and forced a bad throw, which linebacker Thomas Keiser picked off at the Denver 33. The Chargers (7-7) got a field goal to go up 10. Denver answered with a field goal but couldn't recover the onside kick. Manning's final numbers were decent - 27 for 41 for 289 yards and two touchdowns - but padded during desperation time. As most veterans do, especially this time of year, Manning griped about the short turnaround between a Sunday and Thursday game, the likes of which have become more common since the NFL started scheduling midweek contests for almost every week. Adding to the fatigue: Denver ran 91 plays on offense while scoring 51 points Sunday in a blowout over Tennessee. Did the (91) plays on offense take a toll? I can't answer that," Manning said. Now, he'll get 10 days to chew on it. It was the first regular-season loss at home for Denver in 14 tries, dating to last September against Houston, back when Manning was still getting his footing in Denver and the Texans, who happen to be Denver's next opponent, were still good. "A Thursday night game, second division game, you're never sure what you're going to get," Manning said. But it's been that way all season for us. Teams play us different than they play other teams. Whatever it was, it worked for the Chargers, who started gaining some confidence against Denver when they scored the final 14 points in a 28-20 loss to the Broncos last month. Doesn't hurt that they're coached by Manning's former offensive coordinator, McCoy, who won the opening coin toss and boldly deferred, giving the Manning the ball first. Manning marched the Broncos 67 yards in seven plays for a quick score and this had the looks of a typical blowout for a team that's cracked 50 points three times this year. Not so fast. His every move well diagnosed, Manning had two passes knocked down at the line of scrimmage. Chargers defenders wrapped up on Denver's receivers, holding those much-coveted yards after catch to a minimum after so many of Manning's typically short timing routes. Not having to worry about Wes Welker, out with a concussion, they blanketed the other receivers and turned fourth-stringer Bubba Caldwell into Manning's prime target. A good bet. Caldwell led Denver with six catches for 59 yards and two touchdowns, while none of the other Denver receivers did much harm. Denver's previous low in scoring was 27 points against the Chiefs. The defense, meanwhile, was poor once again - not Super Bowl material on this night. The most telling sequence came in the third quarter when Rivers moved the Chargers from their 1 to midfield over 12 plays. Denver committed two costly penalties - an offside when San Diego had the punt team out on fourth-and-4, then a 12-men-on-the-field that set up first-and-5 and allowed the Chargers to burn more clock. Though they didn't score, they ate 8:20 off the clock and flipped the field. "We didn't mention one word about time of possession this week," Rivers said. We said, 'We've got to score.' Time of possession is only important if you're scoring. They scored more, and now, the Broncos must sweat out the race in the AFC. Their three losses are now equal with New England and Kansas City. Denver owns the tiebreaker against the Chiefs but not against the Patriots. Their next two games are against Houston and Oakland - combined record 6-20 - but after a home loss to another losing team, suddenly anything seems possible. Notes: The Broncos had their 10-game winning streak against the AFC West snapped. ... Allen has now scored four touchdowns in the last two games. ... Broncos rookie DT Sylvester Williams recorded his first career sack.