The 24-year-old Frenchwoman won her first career match against Williams earlier this year in Dubai, and despite losing the opening set 6-1 to the five-time Wimbledon champion, it was Cornet who found another gear while Williams looked lost on court No. 1.
Williams dropped the second set 6-3, and despite a late break in the third set to give her a chance at a comeback, it was Cornet who served it out and won the biggest Grand Slam match of her career.
Serena will be 33 in September, something a lot of tennis fans forget considering she won two Grand Slams a season ago and two in 2012, but aging is not something that normally sits well with this sport's athletes.
Get older, get forgotten, at least in the sense of winning big tournaments, and now Williams has failed to make the quarterfinals in any of the 2014 Slams.
This upset might have been the most surprising considering it comes on a surface that has been kind to Williams over the years, but it really shouldn't be. Serena has now been bounced before making it to the quarterfinals at this championship in three of the last four years, and while this is her earliest exit since '05 at Wimbledon, it's more of a tell of where her game is at the moment than anything else.
• Rafael Nadal dropped his opening set for the third straight match at this tournament, but recovered as he has in his two previous matches, beating Mikhail Kukushkin in four sets.
David Beckham watched me lose to Sharapova on Center Court at Wimbledon. Id say that is half winning...— Alison Riske (@Riske4rewards) June 28, 2014
American Alison Riske, after losing to Maria Sharapova 6-3, 6-0 on Saturday at Wimbledon.
This Sunday is a rest day at Wimbledon, so no action on grass, but we will be back on Monday for full second-week action from the greatest tennis tournament in the world.