Published: 02:59 BST, 1 September 2018 | Updated: 03:41 BST, 1 September 2018
Former NFL player Colin Kaepernick received an enthusiastic welcome from fans at the U.S. Open's showcase match between Serena and Venus Williams on Friday night when he was shown raising his fist on the big screen.
The 30-year-old, who was a quarterback at the San Francisco 49ers for six years and sparked a national debate when he knelt during the national anthem during the 2016 NFL season to protest racial injustice and police brutality, smiled at the cheers.
Former 49ers safety Eric Reid, who protested alongside Kaepernick and who like his former team mate remains unsigned, also received a warm reception when he was also shown raising a fist at a packed Arthur Ashe Stadium.
Colin Kaepernick and Eric Reid watched Serena beat Venus at the match on Friday evening
The two football players received loud cheers when they were shown on the big screen
After the game, Kaepernick tweeted: 'Took my niece to see @serenawilliams and @venuswilliams play tonight with @E_Reid35 at Arthur Ashe stadium. Lani lost it when Serena surprised her after the match!!! Thank you so much Serena!!!'
Kaepernick and Reid have both filed collusion grievances against NFL owners and league over the fact that neither