"I think it just shows the depth of women's tennis right now", the 23-year-old Keys told reporters.
Federer and Williams cruised into the third round with straight-sets victories on Wednesday, looking at home on the Centre Court where they have won 15 titles between them.
Federer again opted to skip the clay-court season to prepare himself for Wimbledon and will take some stopping as he goes in search of a 99th tournament triumph at the All England Club.
"It's nearly as if he doesn't need to play tennis matches, it comes so natural for him".
Outside of the Williams sisters, who have 12 Wimbledon titles between them, Keys is viewed as the next likely U.S. champion at the All England Club. Federer added: "I'm happy with how I'm hitting the ball".
France, Uruguay set date for quarter-finals
Santos had bristled at a question about the team's dependence on Ronaldo before Saturday's match, brushing it off with a wry joke. The Fisht Stadium also saw the first group match of Portugal , against 2010 World Cup victor Spain .
Federer was relentless as he lost just nine of 61 total points behind his intimidating service.
"I feel good. Body has behaved", Raonic said.
French 17th seed Lucas Pouille fell short in five sets after fighting from two sets down to be beaten 6-4, 6-2, 6-7 (8-10), 3-6, 6-2 by Austria's Dennis Novak. "It's like 7-6 in the fifth and it's been like an hour and a half!"
Even ultimate warrior Williams, who was unable to defend her 2016 Wimbledon title a year ago because she was pregnant, applauded a couple of her opponent's winners late in the second set before completing victory in 66 minutes.
Former world number one Karolina Pliskova finally made it to the third round on her seventh visit to Wimbledon after seeing off two-time Australian Open champion Victoria Azarenka 6-3, 6-3.
Serena Williams of the United States returns to Viktoriya Tomova of Bulgaria during their third round match at Wimbledon on Wednesday.
"It was better than the first round".