LONDON -- Sloane Stephens is hardly accustomed to leaving a Grand Slam tournament this quickly.
The 18th-seeded American's run of reaching the second week at six consecutive majors -- the longest active such streak among women -- ended abruptly Monday at Wimbledon with a 6-2, 7-6 (6) first-round loss to 109th-ranked Maria Kirilenko of Russia.
"It feels like the end of the world now, but fortunately it's not," Stephens said, shaking her head. "So that's a good thing. You've just got to go back and keep working."
She saved five match points while serving and trailing 6-5 in the second set. But in the tiebreaker, a wide forehand from Stephens allowed Kirilenko to convert her sixth match point.
Vandeweghe, who had lost in the first round on her three previous appearances at Wimbledon, defeated Garbine Muguruza 6-3, 3-6, 7-5.
The 20-year-old Muguruza, the No. 27 seed at Wimbledon, made an impression in Paris where she beat Williams in straight sets before reaching the quarterfinals.
Vandeweghe, a 22-year-old Californian, won her first WTA tournament last week on grass in the Netherlands as a qualifier. She improved to a career-best 51st in rankings released Monday.
For Stephens, coming into Monday her career record in Grand Slam matches was 31-12 (a .721 winning percentage), while she is only 55-54 (.505) in all other main-draw matches.
So it's become something of a theme when it comes to the 21-year-old, who is based in Florida. Since a semifinal showing at the 2013 Australian Open, Stephens had made it to at least the fourth round at every major. Last year at Wimbledon, she got to the quarterfinals before losing to eventual champion Marion Bartoli.
When a reporter began a question about the end of her second-week Slam success, Stephens interjected: "The streak is broken. I'm so sorry to all of you who don't have to write about me this week and next week. I'm so sorry."
Said Kirilenko: "I didn't really think about the results she had before."
Kirilenko's ranking is rather misleading. She has been ranked in the top 10, and played in the quarterfinals at the All England Club two years ago.
But she has been troubled by injuries that limited her to only five matches in 2014 ahead of Wimbledon, including to her left knee. A more recent left wrist problem resulted in the Russian hitting only slices on the backhand side until about a week ago.
"I haven't played such a long match in a long time," Kirilenko said about Monday's victory. "I didn't play for a long time, but the game is there. I didn't lose my game. I just need some more matches and to go through difficult moments when you get tired. So today was a big plus for me."
The loss continued the Australian's poor run at Wimbledon, where she has never advanced past the third round and where she has lost in the first round six times in her 12 appearances at the All England Club.