Kansas City (2-2) laid a thorough 41-14 beatdown on the visiting Patriots (2-2) on Monday night.
Alex Smith threw three touchdown passes, two of them to Jamaal Charles, who added another on the ground.
The Chargers (3-1) pulled a half-game ahead of the idle Broncos (2-1) with a 33-14 thrashing of the visiting Jaguars (0-4).
Philip Rivers threw for 377 yards and three touchdowns, including two to former friend Eddie Royal.
Is there such a thing as a moral victory in a losing effort for a Super Bowl favorite?
Honestly, we're not sure.
After second-half collapses had left Denver holding on for one-score wins in their first two games, the Broncos outscored the Seahawks 17-3 in the third and fourth quarters on Sunday.
San Diego (1-1) remained a game behind Denver in unlikely fashion, thumping the visiting Seahawks 30-21.
Philip Rivers threw three touchdown passes to Antonio Gates, and the Chargers dominated possession by holding the ball for 42:15.
For the second straight week, the Broncos (2-0) jumped out to a big lead and held on for a narrow seven-point victory.
Peyton Manning was 21/26 for 242 yards and three touchdowns.
Kansas City (0-2) finished with more first downs (28-19) and total yards (380-325), and dominated the time of possession (36:14-23:46).
What’s a Broncos season opener without multiple touchdown catches by Julius Thomas? Couldn’t tell you, actually.
Thomas, who scored twice in the 2013 season opener against Baltimore, caught seven passes for 104 yards and three scores.
Rahim Moore nabbed two interceptions, and Montee Ball added 83 yards from scrimmage and a touchdown.
They were never likely to challenge Denver for the AFCW title, but there's still something comforting about seeing the Chiefs and Raiders open in losing fashion.
Knowshon Moreno lit up New England in his Dolphins debut, rushing for 134 yards and a touchdown on 24 carries.
Miami took down the visiting Patriots 33-20 by shutting them out 23-0 in the second half.
The Broncos outgained the Cowboys 357 to 165 in yardage, C.J. Anderson punched in a one-yard touchdown, and Kapri Bibbs scored twice.
Brock Osweiler threw for 190 yards and ran for 29 more, while Isaiah Burse added 153 all-purpose yards.
Peyton Manning threw for 243 yards and two picturesque long touchdowns to Emmanuel Sanders, who returned from a nagging quad injury in electric fashion.