The Arizona Cardinals and Dallas Cowboys sent their own defiant message to United States president Donald Trump before their game on Monday night with a new form of protest.
Instead of kneeling during the American national anthem, as dozens of players had done over the weekend, the Cowboys briefly did so beforehand, filing onto the field alongside owner Jerry Jones and coach Jason Garrett.
Both teams then stood arm-in-arm for the anthem to show their solidarity for the ongoing league-wide protests, with the Cardinals lining up at the end zone just in front of singer Jordin Sparks and the Cowboys returning to the sidelines.
A huge American flag that covered the length of the field had been unfurled prior to the anthem by dozens of fans, military and law enforcement veterans.
On Friday Trump described players who had knelt or raised fists for the Star-Spangled Banner over perceived racial injustice as "sons of b******" and suggested they should be fired by team owners.
Rather than deter players, there were widespread protests two days later, beginning with more than 20 players kneeling at Wembley before the Jacksonville Jaguars' victory over the Baltimore Ravens.
Three teams - the Tennessee Titans, their opponents the Seattle Seahawks and the Pittsburgh Steelers - remained in the locker rooms or tunnel for the anthem, with the exception of Steelers lineman and US Army veteran Alejandro Villanueva who later said he had "unwillingly made a mistake".
Speculation had been rife as to how the Cowboys - who have been nicknamed America's Team - would react to the protests, and a few hours before Monday night's game Trump had tweeted: "Tremendous backlash against the NFL and its players for disrespect of our Country. #StandForOurAnthem".
Boos could be heard echoing through the University of Phoenix Stadium from the gathered crowd as the Cowboys took to their knees, but the team later tweeted a picture of their protest alongside a defiant hashtag #FootballsFamily.
Meanwhile, Cardinals president Michael Bidwell released a statement prior to Monday night's game, saying that football should inspire rather than divide.
He said: "I am extremely proud of our players and the contributions they make that extend well beyond the playing field. There are countless examples of the positive influence and extraordinary impact these players have on our community.
"Football is something that has always united us as Americans and, particularly in times like these, has the ability to inspire rather than divide. It's a responsibility in which we have always taken great pride and will continue to embrace."
Trump posted a series of tweets on Monday, in which he insisted "the issue of kneeling has nothing do with race" and again called on the NFL to respect the anthem.
He also wrote: "Many people booed the players who kneeled yesterday (which was a small percentage of total). These are fans who demand respect for our Flag!"