Serena Williams backs Colin Kaepernick in controversial ad campaign

Serena Willaims

New York: Serena Williams reiterated her admiration for American football player-turned-activist Colin Kaepernick on Tuesday, and praised apparel-maker Nike for featuring him in a new ad campaign (above).

"Especially proud to be a part of the Nike family today. #justdoit," the 23-time Grand Slam champion tweeted before she headed out to book a US Open semi-final berth with a 6-4, 6-3 victory over Karolina Pliskova.

Colin Kaepernick

The ad led to a mass boycott of Nike products online after Kaepernick was castigated by President Donald Trump and other conservatives for kneeling during the national anthem to protest against racial and social injustice, a demonstration he initiated in 2016.

The new advertisement saw the US apparel manufacturer's shares fall by 3.2% with #BoycottNike trending on Twitter. Former San Francisco 49ers quarterback, Kaepernick has been blacklisted by the NFL.

However, Williams told reporters in New York that she thought the company had made a very "powerful" statement.

Catch up on all the latest sports news and updates here. Also download the new mid-day Android and iOS apps to get latest updates