All in all it has been a mixed week for the Murray family. On Wednesday Andy confirmed he would probably miss the rest of the season to let his hip heal; on Friday his elder brother Jamie combined with Martina Hingis to reach the final of the mixed doubles with a tense but convincing 6-4, 7-6 (8) win over Horia Tecau and Coco Vandeweghe.

Murray and Hingis, the Wimbledon champions, got the job done in a tight tussle on the intimate, half-filled Grandstand court but they were not complaining. While mixed doubles is on the outer periphery of the competitive game, it has its devotees and there was much to admire in the touch and artistry on show, especially from Murray.Hingis, the 37-year-old Swiss who won five slams in singles and whose late career has blossomed since she returned four years ago to shake up the doubles scene, said: “Jamie carried me pretty much for an hour and half. I’m the older player. But he did great.”

When asked what was the secret of their success, Murray, smiling broadly, said. “I picked the best partner. We’ve fought through some super tough matches. She made some great shots at the end there, off the baseline. We’re looking forward to the final.”

It was ideal preparation for Saturday’s final, where they will be favoured to win a second major title when they play the third seeds, Taiwan’s Chan Hao-ching and the New Zealander Michael Venus. While reaching for glory, they will not lack for financial incentive.

Murray and Hingis, who are unbeaten since pairing up at Wimbledon this summer, would have shared a relatively puny $30,000 if they had lost on Friday [$20,000 less than a first-round loser in the men’s and women’s singles draws; the singles champions each take home $3,700,000], but are now guaranteed a $70,000 pot as finalists and would split $675,000 if they won the title.

It was not easy. Murray gifted their opponents set point when he butchered a drop shot in the second set tie-break, and Vandeweghe – who was devastated after losing in the singles semi-finals to compatriot Madison Keys on Thursday - grabbed another with a sublime lob. Tecau turned villain, netting a simple volley. Hingis grabbed match point with an uncompromising drive down the middle and Murray stepped up to finish the job, forcing a final wide return from Tecau.

Hingis, who came out of a six-year retirement in 2013, is also in the women’s doubles final on Sunday, but said her body, “was holding up OK”.

Earlier the Dutchman Jean-Julien Rojer, who partnered Tecau to win the men’s doubles title, beating the Spaniards Feliciano and Marc López 6-4, 6-3 on the Arthur Ashe court, celebrated with a passionate denunciation of racism and explained the significance of the Statue of Liberty shirt he has been wearing throughout the tournament.

Rojer said the image of the New York statue bound in red, white and blue, signified his commitment to justice and democracy.It struck a chord with the crowd and then with journalists unaccustomed to hearing players stray into social commentary. Tennis, like golf, is assertively apolitical, here and elsewhere.

“It’s funny. In the beginning I wasn’t getting questions,” Rojer said of his T-shirt. “Once we made the semi-finals you get a little bit more attention and more press. I’m glad it worked out that way, because I have Lady Liberty on the front of the shirt and a jacket that I wear with the Statue of Liberty on the front and a peace symbol on the back.

“I have been here since I’m 12 years. It’s where I started playing tennis and it gave me my opportunity to play. I just wanted to get the conversation going, promoting freedom and justice, liberty for everybody on gender issues, on racial issues, which we deal a lot with in this country.

“In tennis we don’t say much about it. But this is just tennis; we deal with real life issues out there. And especially I think it’s symbolic to be here. This is New York City. I heard a story of a gentleman who saw my jacket, a firefighter. He liked it.

“I’m not like a political symbol here, [but] I come from Curacao [a former Dutch colony 40 miles off the coast of Venezuela], different races and ethnicgroups that live together. First time I noticed colour was when I came to the US, sad to say. I see a lot of unfair stuff going on. Some of these people don’t have a voice to defend themselves.

“It really came about after Charlottesville [where neo-Nazis clashed with anti-fascists last month], and I thought [the T-shirt] was a good message. You can never say too much stuff for equality for everybody in this country. That message needs to be passed on constantly. Maybe I change five people’s minds. It’s a step in the right direction.”

Tacau, who has played with Rojer for four years, endorsed Rojer’s comments.

“Jules is an outspoken guy,” Tecau said. “He’ll talk more than other players but I think, as role models for the generations behind us, the young generation, it’s important to say that. We’re not just athletes competing for slams and prizemoney and glory. We try to compete in sports and get better and improve and all that. In the locker room, everybody is the same.”