MILLMAN UNSEEDED SENDS FEDERER CRASHING OUT OF US OPEN

Matching Nishikori's results on the court may prove far easier than keeping pace with the popular athlete when it comes to endorsements.

Despite having never won a Grand Slam, just 11 career tournaments and none since 2016, Nishikori is in the same league as Grand Slam kings Roger Federer and Rafa Nadal when it comes to pitching products.

Federer, the winner of a record 20 Grand Slams, is the best paid tennis player at seventh on Forbes' 2018 list of highest paid athletes, having earned $77.2 million, including $65 million from endorsements.

Nadal, whose resume includes 17 Grand Slams, sits 20th on $41.4 million while Nishikori checks in as tennis's third highest earner with $36.4 million, matching Welsh soccer player Gareth Bale in the rankings.

When it endorsements, million is no comes Nadal's match to $27 for Nishikori, who pockets $33 million off the court. OSAKA STOCK RISING Just 20-years-old and playing in her first Grand Slam quarter-final, the charismatic Osaka could soon find herself in a similar situation keeping company with women's endorsement titans Serena Williams and Maria Sharapova.

Osaka's stock is clearly on the rise. She collected her first career win at Indian Wells earlier this year and came into Monday's fourth round US Open clash having won 22 consecutive games.

"Every time I play a Grand Slam, people ask me am I going to go farther than the third round," said Osaka, the first Japanese woman in the US Open last eight since Shinobu Asagoe in 2004.

"Then in Australia I went to the fourth round, then people were like, are you going to go farther than that or is that where you're going to stop?

"I've always dreamed of playing here and going to the quarterfinals and further. So I'm just glad I could do one of my goals."

Next up for Osaka is Ukraine's 36th-ranked Lesia Tsurenko.

While Nishikori has never won a Grand Slam he has been to a final, losing the 2014 US Open to Marin Cilic.

Four years later a resurgent Nishikori, fighting his way back from injuries, will get his shot at revenge when he takes on the bighitting Croatian for a spot in the last four.

"This year is easy for me, because I don't expect any big result," said Nishikori. "I try to play one match at a time. This week it's been great.

"Every match I been playing really good tennis, and, well, maybe I had more pressure few years ago.

"Right now I don't have any pressure, but also enjoying playing every match and enjoying playing tennis again little more than before." it's crazy. It's a really good show, but for the players sometimes it's tough, especially for me.

"I just tried to be focused. I tried to think about not too much things, just my work, my job. Today it worked."

The Spaniard will meet last year's runner up Madison Keys in the quarters and knows she will be the underdog against the 14th seeded American.

"It will be a really tough match. She is from the United States so the crowd will probably help her," Suarez Navarro added.

"I need to be aggressive ... try to be solid, run and fight. This is the way that I can play really good tennis. I have the character inside, sometimes I have to show more but, well, I'm working on that."