LONDON — Madison Keys started thinking ahead to facing Serena Williams at Wimbledon. Here's the problem: Keys was playing someone else at the time.
And so Keys, the U.S. Open runner-up and French Open semifinalist who was seeded 10th at the All England Club, went from a big lead to a real tussle in a test of wild momentum swings and wound up losing her third-round match to 120th-ranked qualifier Evgeniya Rodina 7-5, 5-7, 6-4 Friday.
"Honestly," Keys said, "I think today was a massive mishandle of nerves."
She was ahead 5-2 and seemingly comfortably on her way to the expected victory when everything went awry.
"I felt my mind go and move on," Keys acknowledged. "I don't think I did a good job of keeping in the moment and playing the person who was in front of me."
That was Rodina, a 29-year-old Russian who entered the day never having made it to the fourth round at any Grand Slam tournament, with a career tour-level winning percentage of .408, and zero victories over anyone ranked in the top 20.
"Of course, I am surprised a little bit," Rodina said afterward, "because I won."
After digging herself into that early deficit, Rodina won nine games in a row to grab the first set and move ahead 4-0 in the second.
"I was distracted for a game or two, and then I became more nervous because I felt like I let a lead slip. ... I started playing passive. I kind of started playing not to lose, which doesn't usually work out well for me," Keys said.
"Then," she added, "it kind of quickly spiraled."
Still, somehow, Keys steeled herself momentarily.
She managed to slow down Rodina just enough to win 7 of 8 games and force a third set, relying on the two best aspects of her game: a powerful serve and powerful forehand. Keys ended up with 15 aces.
Rodina's take on Keys: "She hits so hard."
Keys again seemed to lose her way in the third set, the only one of the match in which she had more unforced errors (18) than winners (14).
She also was broken three times in that set alone, seven overall in the match. Keys came in having won 18 of her 19 service games through the first two rounds.
"I was just constantly playing back and forth between playing too passive and then getting my mind back right and playing better," Keys said. "It's tough to go back and forth like that."
Now it will be Rodina, not Keys, meeting Williams on Monday with a quarterfinal berth at stake.