After dropping a set for the first time in the tournament, Rafael Nadal raced away from Marin Cilic to reach the US Open last eight.
Injury dropped Belinda Bencic outside the top 300 in 2017, but she always believed she could return to the upper echelon of women's tennis.
A third five-set victory in four matches proved beyond Alexander Zverev as he lost in the US Open fourth round to Diego Schwartzman.
Despite being defeated by Belinda Bencic, Naomi Osaka expressed satisfaction with a US Open campaign that has seen her grow as a person.
Ashleigh Barty will return to the top of the WTA rankings after the US Open following Naomi Osaka's defeat to Belinda Bencic.
For Novak Djokovic, losing ground in his pursuit of the grand slam singles titles record will sting more than his injured shoulder.
Despite having an idea he was playing a wounded Novak Djokovic, Stan Wawrinka was still surprised by his opponent's retirement in New York.
After ending his US Open defence prematurely, world number one Novak Djokovic spoke of the pain he has dealt with in his left shoulder.
Stan Wawrinka was in command against Novak Djokovic when the defending champion retired at the US Open.
World number one Novak Djokovic saw his US Open defence end as he retired in the third set against Stan Wawrinka.