Safety Rahim Moore made a second-down run stop and cornerback Chris Harris deflected a third-down pass attempt to force the Chargers’ third straight three-and-out.
San Diego punter Mike Scifres sent it 40 yards and Denver took over at their own 44-yard line, trailing 7-0.
Running back Willis McGahee gained the first 20 yards of the possession with a pair of rushes for 15 and 5 yards.
Wide receiver Matthew Willis then gained 10 yards on a screen pass followed by an 8-yard carry from McGahee that picked up a first down and brought Denver to down to the 13-yard line. McGahee and Chargers cornerback Quentin Jammer – the tackler — were helped off the field by trainers after the play.
On the next play, quarterback Peyton Manning threw it to wideout Demaryius Thomas in the back left corner of the end zone. Thomas caught the pass but was initially ruled out of bounds. The Broncos challenged the ruling and it was overturned, as officials determined that Thomas touched both feet in bounds with possession.
Matt Prater converted the extra point attempt and the Broncos tied the game at 7-7 with 12:57 remaining in the first half.
The touchdown pass gave Manning sole possession of second place in NFL history with 421 career touchdown passes. He passed Dan Marino and now trails only Brett Favre.
The touchdown catch was Thomas’ fifth of the year.
The drive covered 56 yards on six plays and took 2:17 off the clock.
Click here for the audio highlight of the touchdown.