WIMBLEDON, England -- Teenagers -- and parents know this better than anyone -- operate in their own insular world. Focus, concentration and poise are not words that usually come to mind.
And then there is Sloane Stephens.
Only 19, she finds herself on the verge of reaching the second week of her second straight Grand Slam. Against the 25th-ranked player in the world Wednesday, Stephens constantly found herself running into and digging out of trouble. She saved five set points in the first set alone. In the third set, she was down love-30 on every single service game.
"I was saying to myself, 'Oh, my God, this is just ridiculous,' " she explained later. "I do have some lapses where I have a brain fart. But I'm working on my focus and concentration."
It's starting to have an effect. Stephens beat Petra Cetkovska 7-6 (6), 6-4, 6-3 and now will face Sabine Lisicki in a third-round match Friday.
"I wish there was a secret I could tell you," she said of her newfound calm. "But it just happens."
Her mother, Sybil Smith, who introduced Stephens to the game when she was 9, has seen the transformation.
"It's a choice to change your mental approach," Smith said. "You are the only person who can do this. Her coach pounds it into her; her mother pounds it into her. Yes, she's getting better."
It's early, to be sure, but here are a few nifty numbers to contemplate: Serena Williams was 10-5 in her first five Grand Slams. In the same number of Slams, Stephens is 8-4. That's precisely the same ratio of startling precocity.
"Oh, really?" Stephens said, sounding genuinely pleased. "That's kind of cool. We're besties, so it all works out."
Indeed, Stephens and Williams have become terrific friends. The first tennis match she remembers ever watching was the 2003 Wimbledon final, when Serena beat sister Venus. They talk all the time and, according to Stephens, agree on virtually every subject.
"I say to her, 'You're my friend, but you're such a goofball,' " Stephens said. "That's my girl. She's so cute. I love her to death."
Clearly, Stephens is a social person. Lisa Leslie, the basketball star, is here watching her play.
Stephens' calm amid the storm is remarkable to watch. Against Cetkovska -- a professional for a decade -- she was the cooler player in the critical moments. After she squandered a 5-3 lead in the first set and managed to scrape through the tiebreaker with a down-the-line backhand winner, she made a fist -- but shook her head at the same time.
"When I was younger, I was freaking out and throwing rackets and stuff," Stephens said. "But focusing makes me relax. I play like I'm sitting on my couch."
That's how she handles her interviews, too.
When Stephens was asked about Frenchman Gilles Simon's criticism of the equal pay women receive at the Grand Slams, she responded, "Whatever he says means nothing to me."
She went on to tell the story of her first encounter with Simon, as a 10-year-old ball girl in Sunrise, Fla. Simon, she said, hit her in the chest with a ball and didn't apologize. A year later, he tried to push her off a practice court in Estoril, Portugal.
"Yeah, whatever," she said.
Stephens was asked if she was scared of the serves she'll be seeing in her next match from Lisicki, a semifinalist here last year. She wrinkled her nose and her left eyebrow arched.
"Uh, no," she said. "Does she have a big serve?"
Lisicki hit one here last year at 124 mph -- roughly the same as Roger Federer and Novak Djokovic.
No sense of shock and awe over where she finds herself -- this is how Stephens operates. And this is why she keeps advancing through important tournaments.
Only once this year has she lost to a lower-ranked player. Her year-end ranking has improved dramatically -- from No. 802 in 2009, to No. 198 a year later, to No. 97 last year. Stephens is currently ranked No. 59 among WTA players, one spot behind Venus Williams. When this tournament ends, she'll move ahead of Venus and will be inside the top 50.
"There is no room for error at this level," she said. "For me, it's been a big thing to keep grinding and stay focused."
On the first day of the tournament, Heather Watson became the first British woman to win on Centre Court in 27 years after besting Iveta Benesova. And now she's through to the third round after beating Jamie Lee Hampton of the United States 6-1, 6-4.
Another American, Coco Vandeweghe, had a more brief, but no less, bitter experience. She resumed her match from Tuesday, facing match point against Sara Errani. After missing her first serve, she double-faulted and -- with two errant strokes -- the match was over. The whole thing took seven seconds. However, both players were smiling when they met at net.
Christina McHale, the 20-year-old from New Jersey, had her second-round match against Klara Zakopalova pushed to Thursday because of rain. McHale won her first-round match over Johanna Konta 10-8 in the third set.