The start of the NFL season was overshadowed by some fans booing during a moment of silence which the league said was "dedicated to the ongoing fight for equality in our country".
Players from the Kansas City Chiefs and Houston Texans linked arms at Arrowhead Stadium before the game got under way, but some jeers were heard in a crowd that was less than a quarter full because of Covid-19 restrictions.
Racial tensions have been building in the wake of the death of George Floyd while in police custody in Minnesota in May, sparking a wave of protests across the country.
Texans defensive end JJ Watt told the NFL's official website: "The moment of unity I personally thought was good. I mean the booing during that moment was unfortunate. I don't fully understand that. There was no flag involved.
"There was nothing involved other than two teams coming together to show unity."
Kansas City mayor Quinton Lucas said on Twitter: "We're a good city of good people. I heard boos too.
"But we also have hundreds of thousands more around here who respect the message the players are sharing; who respect the rights of our players and people to voice a strong message and who are working to make us better each day."
Chiefs defensive end Alex Okafor took a knee and raised his right hand during the national anthem, with the Texans staying in the changing room in a demonstration against racial injustice.
When play got under way Chiefs quarterback Patrick Mahomes threw for 211 yards and three touchdown passes as the Super Bowl champions overcame the Texans 34-20, with around 16,000 fans in attendance at the 80,000 capacity stadium.
The first score of the 2020 season went to David Johnson, who capped a nine-play drive with a 19-yard run as the Texans went into the first break 7-0 up.
But Mahomes hit Travis Kelce early in the second to draw things level, with a two-yard completion to Sammy Watkins putting the Chiefs ahead.
Clyde Edwards-Helaire had a 27-yard rushing TD, while Mahomes capped off his night with a three-yard pass to extend the lead to 31-7.
Deshaun Watson led two scoring drives in the final quarter for Houston, but a Harrison Butker field goal saw the Chiefs home and dry.
