In a rematch from last season's AFC Championship game – where the Bengals beat the Chiefs to advance to the Super Bowl – quarterback Joe Burrow was at his sharpest.
The 25-year-old former top overall draft pick completed 25 of his 31 passes, including touchdown passes to Tee Higgins in the second quarter and Chris Evans in the last, with Evans' score putting the Bengals up for good.
In his return from a four-game injury absence, last year's Offensive Rookie of the Year Ja'Marr Chase picked up right where he left off as Burrow's top option, catching seven passes for 97 yards, but backup running back Samaje Perine was even more influential.
Perine was used heavily in the fourth quarter as the Bengals looked to claw their way back from a deficit, with three of his six catches coming on their go-ahead touchdown drive, finishing with 49 yards through the air and another 106 on the ground from 21 carries.
It was not the best game from Chiefs quarterback and MVP favourite Patrick Mahomes, with 223 yards and one touchdown, as the Bengals committed to dropping eight defenders into coverage all game, forcing the Chiefs to accept small gains instead of their usual chunk-plays.
With the win, the Bengals are now 8-4, joining the Baltimore Ravens in a tie for the AFC North lead, while the Chiefs are three games clear atop the AFC West at 9-3.
Purdy party keeps the 49ers rolling
Purdy, the very last pick in this year's NFL Draft, was called upon when starting quarterback Jimmy Garoppolo was carted off and ruled out during their first drive of the game. Garoppolo has been diagnosed with a broken foot, with the team saying afterwards that it will end his season.
Almost a lock for the playoffs now at 8-4 with arguably the best defense in the league, the 49ers will need Purdy to get up to speed in a hurry if they still have dreams of a Super Bowl run, and he was solid against the Dolphins, completing 25 of his 37 passes for 210 yards, two touchdowns and one interception.