Serena Williams reiterated her admiration for U.S. football player Colin Kaepernick on Tuesday, and praised apparel maker Nike for featuring him in a new ad campaign.
"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.
The ads prompted immediate calls for Nike boycotts over Kaepernick, as the former quarterback for the San Francisco 49ers, Kaepernick has been effectively blacklisted by the NFL, and Nike shares tumbled early Tuesday over worries a campaign around such a controversial figure could harm sales.
Williams told reporters after her victory over Pliskova that she thought the company made a "powerful" statement.
"He's done a lot for the African American community, and it's cost him a lot," Williams said. "It's sad. But he continues to do the best that he can. Having a huge company back him, you know, could be a controversial (decision) for this company, but they're not afraid," added Williams, who has had an endorsement deal with Nike since 2003. I feel like that was a really powerful statement to a lot of other companies."
Williams fought back from a break down in the first set to beat Czech eighth seed Karolina Pliskova 6-4 6-3 and reach the semi-finals of the U.S. Open in suffocating conditions at the Arthur Ashe Stadium.
Two successive breaks of serve allowed Williams to win her eighth game in a row and open up a 4-0 lead, and she saw off a brief fightback from Pliskova before sending down her 13th ace to seal the match in one hour and 26 minutes.
"When I get to a Grand Slam, I feel I want to play really hard. I want to do really well. I love this game so maybe that's why," added Williams, who was beaten by Pliskova in the 2016 semi-finals.
Next up for the American is a semi-final clash with 19th seed Anastasija Sevastova of Latvia.