Reigning Super Bowl champions Kansas City Chiefs suffered the worst possible start to the defence of their title as the Detroit Lions ran out 21-20 winners at the Arrowhead Stadium.
A nine-yard pass from Jared Goff to Amon-Ra St. Brown saw the Lions register the opening touchdown of the NFL season in the first quarter, before Patrick Mahomes unsurprisingly led the Chiefs' fightback.
The 2022 MVP picked out Rashee Rice and Blake Bell from close range to propel the Chiefs into a 14-7 lead at the half-time interval, but the absence of tight end Travis Kelce - who is nursing a knee injury - was doing the champions no favours.
Rookie Brian Branch intercepted a Mahomes pass in the third quarter and ran 50 yards for his first NFL touchdown, although a 35-yard Harrison Butker field goal restored the Chiefs' slender advantage.
Butker repeated his trick from 39 yards in the fourth, but with seven minutes remaining, David Montgomery burst through to the end zone before Riley Patterson's final kick completed the job.
The Chiefs will aim to bounce back when they visit the Jacksonville Jaguars a week on Sunday, where the Lions are next in action against at home to the Seattle Seahawks.
