DENVER (AP) -- Patrick Mahomes rallied the unbeaten Kansas City Chiefs back from a 10-point deficit in the fourth quarter for a 27-23 win over the Denver Broncos on Monday night.
The Chiefs (4-0) took a two-game lead over the Broncos (2-2) in the AFC West with their sixth straight win over their rivals.
Down 23-13, Mahomes directed a 12-play, 75-yard drive that ate up more than six minutes and culminated with a 2-yard TD toss to tight end Travis Kelce, then added a 60-yard touchdown drive, handing off to Kareem Hunt for the 4-yard score with 1:39 remaining.
It was the first time since 2004 that the Broncos blew a 10-point fourth-quarter lead at home.
In between Kansas City's scoring drives, the Broncos, who had run roughshod over the Chiefs all night -- a 7.2-yard average per run -- suddenly abandoned their ground game in favor of three-wide receiver sets that resulted in a quick three-and-out.
Then, struggling punter Marquette King shanked a 35-yarder out of bounds, giving the Chiefs the ball at their 40 with 4:35 left.
Mahomes overcame a couple of flags that put Kansas City in a second-and-30 hole from their 31 and completed a 35-yard pass to Demetrius Harris down to the Broncos' 11 at the 2-minute warning.
The play should never have counted because the play clock expired before the snap, but referee Craig Wrolstad's crew missed it.
After the Chiefs took the lead, the Broncos reached the Kansas City 28, but Case Keenum overthrew an open Demaryius Thomas near the goal line racing down the right sideline. Then rookie Courtland Sutton caught a first-down pass but overhanded it back on a failed hook-and-ladder that resulted in a turnover on downs with 5 seconds left.
Phillip Lindsay's 1-yard TD run broke a 13-all tie late in the third quarter, and Brandon McManus extended the lead to 10 with a 46-yard field goal.
Kelce's TD catch got the Chiefs within three with 6:27 remaining. Denver's three-and-out and shanked punt gave the Chiefs the ball at their 40 and brought the Broncos' exhausted defenders right back onto the field with 4 1/2 minutes remaining.
The officials had another big blunder when Mahomes was about 1 1/2 yards past the line of scrimmage when he scrambled and hit Kelce for a 29-yard catch to the 3 early in the second half. Broncos coach Vance Joseph appeared to be reaching for his red challenge flag but never threw it.
Denver's defense bailed out its coach by forcing the Chiefs to settle for Harrison Butker's chip-shot field goal tied it up at 13.
On Denver's first drive of the second half, Keenum threw a 25-yard pass to tight end Jeff Heuerman, but Chiefs defensive back Eric Murray wrested the ball away as they tumbled out of bounds. Heuerman was starting in place of Jake Butt, who sustained his third ACL tear of his career while practicing special teams on Thursday, ending his season.
It was Keenum's sixth interception with Denver, one fewer than he had all of last season in Minnesota.
The Broncos averaged a whopping 8.5 yards per carry in the first half but kept stopping themselves with pass plays even though Keenum had completed 14 of 19 throws at the half.
Royce Freeman took a toss from Keenum and slipped seven tackles on his way to a 14-yard touchdown in which he dragged linebacker Anthony Hitchens across the goal line to tie it at 10. The big play of the drive was a 42-yard catch by Sutton.
The Chiefs also had a big play on their first touchdown drive as Hunt rumbled 45 yards, setting up Mahomes' 8-yard keeper to put the Chiefs on top 10-3.
Denver led 13-10 at halftime.
Broncos wide receiver Demaryius Thomas and linebacker Brandon Marshall both stood with their teammates during the national anthem. Since the preseason, both players had been retreating to the tunnel nearest their bench during the singing of "The Star-Spangled Banner."
Chiefs: Wide receiver Sammy Watkins pulled a hamstring in the second quarter and didn't return. Linebacker Dee Ford (groin) left in the fourth quarter.
Broncos: Right tackle Jared Veldheer left in the first quarter with a knee injury and was replaced by Billy Turner.
Chiefs: Host Jacksonville on Sunday to begin a stretch of three home games in four weeks.
Broncos: Visit the Jets on Sunday, the first of three road games in four weeks.