When Gayle Benjamin invited a friend to travel from his home in Calgary, Alberta, to visit her in New York, she already had tickets to the United States Open women’s final. A devoted fan of Serena Williams, Benjamin never thought that Arthur Telesford, her Canadian friend, would become a liability.

But as it turned out, Williams faced a Canadian, Bianca Andreescu, in the final on Saturday, and Telesford, who wore a bright red shirt and a baseball cap with the flag of Canada on it, cheered for his compatriot.

“I told him, don’t wear the red and the Canadian flag,” said Benjamin, a construction manager from New York, “because you will be the only one.”

He was far from it. There were many Canadians sprinkled among the more than 23,000 fans in Arthur Ashe Stadium. They wore red and white clothes adorned with maple leafs and waved Canadian flags as they rooted for Andreescu.