Wearing a crimson jersey featuring No. 25 alongside a Chinese flag, soccer player Nico Yennaris, or Li Ke as he is known in China, sang the national anthem. When he was 20, Yennaris had declared that were he not a professional athlete, he’d be a singer. These days, besides listening to Beyoncé, Drake and Miley Cyrus, he also had a recently downloaded copy of “March of the Volunteers,” the Chinese national anthem, on his phone. Yennaris had been studying it in-between practices, waiting for this exact moment.