Next up for Keys, who was routed by Sloane Stephens in last year's final, is the victor of the evening clash between five-times Grand Slam champion Maria Sharapova and Spanish 30th seed Carla Suarez Navarro.
After racing through the first two sets against Germany's Philipp Kohlschreiber he dropped his serve while serving for the match at 5-4 in the third, but managed to prevail 6-3, 6-2, 7-5.
This, however, dwarfed it, a win over arguably the greatest of all time to reach his first Grand Slam quarterfinal against a decidedly pro-Federer crowd.
Zverev recently joined the forces with tennis legend Ivan Lendl, and speaking on it Federer said: 'He's been struggling at slams maybe a little bit, sure, but he's still young, so time is on his side. The No. 20 seed had to work much harder than she had so far in the tournament, where she had won 22 consecutive games leading into the match Monday. "He's been a hero of mine and today he was definitely not at his best but I'll take it".
Connor Goldson plays down gap between Rangers and Celtic
It was a fierce encounter at Celtic Park as the pair who previously worked together at Liverpool -with Gerrard as captain and Rodgers manager - met as bosses for the first time.
Nishikori was glad he didn't need more than three sets in the blazing sunshine on Louis Armstrong Stadium.
Keys started the match by holding in the first game and then doubled her lead after a 14-minute game that featured four game points for Cibulkova, who was baking on the sunny side of the court, and five break points for the American.
Millman, ranked 55, could not be less like his compatriot Kyrgios.
It was almost 1am and the temperature was a steamy 82 as Roger Federer tried to hold back the years at the US Open.
Kyrgios umpire criticised by U.S. Open for going 'beyond protocol'
Lahyani stood over the seated Kyrgios, berating the 23-year-old. "I got pissed off", said 2011 and 2015 champion Djokovic. Kyrgios though played down the incident and denied Lahyani was "coaching" him during the drama-filled second set.
"I've got a lot of respect for Roger". A universally popular player who has built a successful career, despite several serious injury setbacks, on never giving an inch. He was up a break in the second set, before his serve began to betray him.
Roger Federer served poorly.
But the two set points came and went and a double fault gave Millman the break back. The Slovak got on the board for 3-1 with a forehand victor down the line, but Keys reeled off the final three games, breaking for 5-1 after Cibulkova punched a backhand volley wide on break point, then holding in the next game with two aces and a backhand down-the-line victor on set point.
Tottenham star Son Heung-min spared military service after Asian Games win
On September 1, the South Korean soccer team won the final match after scoring 2-1 against Japan at the '2018 Asian Games' . The Iranian side dominated the match from the very start and won 25-17, 25-22, 25-21, to successfully defend their title.