He took four bags of intravenous fluid between Saturday night and Sunday morning, and then hurt his right thigh in the second quarter, requiring more treatment.
It was all good, though. Nothing a victory and a fourth straight AFC West title won't cure.
"He was sick. I don't think it was Jordan game flu sick, but he was sick," running back C.J. Anderson said, referring to how sick Michael Jordan was when he scored 38 points in Game 5 of the 1997 NBA Finals.
"He went out there and battled," Anderson added. "He battled the Chargers' D, battled the crowd, battled the adversity and battled himself. That's a lot of battles going on in one man's lifetime right now. But he went out there and overcame it and helped us out with a 'W' today."
Manning said he first started feeling ill Saturday evening.
"I had a rough night. I'm not going to lie, it wasn't an enjoyable night," Manning said. "It came out of nowhere."
"I was in some discomfort and had some limitations," Manning said. "If you can't do your job, you can't move, if you hurt yourself, you hurt the team."
"We were unsure at halftime to be honest with you, until Peyton made the cavalry entrance there at the start of the third quarter," coach John Fox said. "I think it's a tribute to the kind of toughness Peyton has and the kind of competitor he is that he got up and did a tremendous job in those conditions."
Osweiler was warming up "and all of a sudden I heard this loud cheer and I didn't even need to turn around. I knew exactly what it was."
Manning was back in time for Denver's first possession of the third quarter. He capped the second possession with a 28-yard touchdown pass to Thomas to give the Broncos a 16-3 lead.
Denver's 12th straight division road win tied San Francisco's NFL record set from 1987-90.
The Chargers (8-6) entered the game as the AFC's No. 6 seed and saw their wild-card chances diminished. They lost a week earlier to New England.
"It's just a two-game streak against the two top teams in the conference," said Philip Rivers, who threw one touchdown pass and was intercepted twice. "We're not in their company yet. It's not like we've lost to the bottom of the barrel."
Manning completed 14 of 20 passes for 233 yards with one touchdown and no interceptions. He extended his own NFL record to 14 seasons with 4,000 yards passing.
A week earlier, Manning's touchdown streak came to a halt at 51 games, three shy of Drew Brees' NFL record, and he was picked off twice for the fourth time in the past six games.
NOTES: Thomas had six catches for 123 yards and Anderson ran 29 times for 85 yards. ... Broncos left tackle Ryan Clady (thigh) and linebacker Brandon Marshall (foot) left the game and didn't return. ... Butler was spun around by Manning's block and ended up on the ground. He left with an elbow injury. ... Chargers wide receiver Keenan Allen left with an ankle injury.
Copyright 2014 by The Associated Press