A Japanese dream duo of Naomi Osaka and Kei Nishikori could come together for mixed doubles at the 2020 Tokyo Olympics.
World number one Osaka, the reigning US and Australian Open champion, and Nishikori, the 2014 US Open runner-up ranked seventh in the world, could be a formidable combination in the fight for gold next year.
But Nishikori, who addressed the idea Friday as he prepared for the start of the US Open, worried that adding the event to singles and men's doubles might be too much in the Tokyo summer heat.
"I will play men's doubles, for sure. With that condition -- very hot, very humid -- playing singles and two doubles, I don't know if I can," Nishikori said.
"I haven't (had to) think too much yet honestly. I don't know. I will talk to Naomi later."
Nishikori, 29, said it was understandable that 21-year-old Osaka has said this has been a tough year for her. She followed her US Open triumph with an Australian Open win, attained number one then lost and regained -- enduring early exits at the French Open and Wimbledon along the way.
"I'm sure it's going to be OK. I think time will help her to get back to normal," Nishikori said.
"I think it's normal to have that feeling. She suddenly gets number one, winning two Grand Slams, be number one like straightaway. She's still young.
"I'm sure she will think a lot of things -- some things she doesn't have to think. But if she can try hard practicing and play every match hard, I think she's going to be OK."
Osaka said a recent break from tennis helped revive her outlook on the game and her place in it.
"It has definitely changed for me," Osaka said.
"I took a break sort of and relaxed my mind and realized that you have to have fun doing what you love.
"For me, I love tennis. Sometimes I feel like I don't, but I wake up every morning and if I don't play, I feel like I've done nothing during the day.
"I just go out now every day trying to learn something new, trying to just do the best that I can."
Osaka resisted the notion her life is a dream made real, even with two Grand Slams and a top ranking before her 22nd birthday.
"I'm really blessed to be in this position, and then there are bad things that come with that," Osaka said.
"I would never say anything negative about what's going on in my life right now.
"For me, when you say is it a dream, it's like something fluffy, like you're on the beach somewhere sipping a pina colada. I'm right here right now."
Nishikori pondered his own growth and fan base in Japan, wondering if he could have produced the same success under the attention and pressure of living in Japan.
"I have to say, if I lived in Japan, I think I was going to have a different life," he said.
"There's too much attention. I feel like I'm a star there. But I think it's good thing that I live in States."
Nishikori says the US Open always brings excitement and nerve. He produced his best Grand Slam result here five years ago, losing the final to Marin Cilic, and reached the semi-finals in 2016 and 2018.
"I feel a lot of confidence from that memory, playing final first time in Grand Slam. But also I always think that I could play a little better in a final. I lost straight sets. I didn't do well. I hope I can come back to that stage again. I hope I can play differently.