Elina Svitolina surprises No. 5 seed Sloane Stephens at Family Circle Cup

Elina Svitolina won 78 of 140 total points played against Sloane Stephens. (Mic Smith/AP)

CHARLESTON, S.C. -- Elina Svitolina celebrated her first week as the highest-ranked WTA teenager by upsetting No. 18 Sloane Stephens 6-4, 6-4 in the second round of the Family Circle Cup on Wednesday.

Ranked No. 35 and gradually improving, Svitolina fended off two comeback attempts from the fifth-seeded Stephens -- who was down 1-5 in the first set and an early break in the second -- to earn her fourth victory over a top-20 player this season. The 19-year-old from Ukraine avenged a straight-set loss to Stephens at the Australian Open and continued to build on her promising play from the BNP Paribas Open (where she lost a third-set tiebreaker to No. 11 Ana Ivanovic in the second round) and Sony Open (where she pushed No. 3 Agnieszka Radwanska to three sets in the fourth round) over the last month.

Get to know Elina Svitolina, the WTA's highest-ranked teenager

"I've been working hard and believing in myself, so I was waiting for this win," Svitolina said.

Svitolina had her shaky moments as Stephens again played some of her best tennis when trailing.

"She's a good player, because she's playing good on the moments when she's down," Svitolina said. "You've probably seen that she played many matches when she was down 5-2 and she won 7-5. That's what is good from her side, that she's fighting until the end."

Svitolina, a former junior French Open champion, credited her tactics for the win. Solid from the baseline, she kept Stephens on her heels by attacking the net as much as possible. Not every volley worked out -- she laughed about how many shots she missed -- but she never stopped moving forward.

"I'm trying now to go more forward," she said. "This is the key on the clay court. You need to finish the point earlier, because you can play so long and you can run a lot. I'm getting better a bit."

Stephens, who lost to Caroline Wozniacki 6-1, 6-0 at the Sony Open in her last tournament, has spent the week telling reporters that she won't push the panic button just because of a few bad losses.

"I just have to be patient," she said before the tournament. "It's a long year. If I play for 10 more years, I'm going to be doing this all the time. So I've learned that I have a lot of tennis to play and that things may not happen right now or next week, but eventually the things I want to happen will happen."

Sloane Stephens remains the only top-20 player without a WTA title. (Mic Smith/AP)

Wednesday marked Stephens' third opening-round loss in six events this season. She's 4-5 since making the fourth round of the Australian Open, and last year she went 3-5 during the same stretch. The 21-year-old American's ability to perform outside of the Grand Slams continues to be dubious, but Stephens has stressed that she's keeping perspective. She's the only top-20 player who hasn't reached a tour-level final -- in contrast, Svitolina already has two titles -- but she's still in the early stages of what should be a long career.

"I'm in the same spot ranking-wise [as last year]," Stephens said before the tournament. "Had some ups and downs. The end of last year was a little bumpy. The start of this season wasn't great but still pretty decent. But I'm not going to look into it too much. There's still a lot of tennis to be played throughout the year so I'm not too worried about it."

Asked after the loss whether the frustration is beginning to mount, Stephens said it wasn't something she dwells on.

"I think I feel more frustration when I'm down 5-1 and I've made like 58 unforced errors in like 12 minutes," she said. "That's the most frustrating part, when you're in the match and you're doing that. Then after it's just like, 'That sucked,' but I'm able to get over it because I know there are things that I can work on, things that I can do better."

Stephens admitted that she's had to change her mentality after not succeeding consistently following her big win over Serena Williams at the Australian Open last year.

"I just thought you start playing good tennis and you're supposed to win 10 tournaments in a row," she said before the tournament. "But not everyone does that. It's definitely been a learning process."

Last year in Charleston, Stephens was lamenting the pressure and expectation she felt as the rising No. 2 American. She said she couldn't wait to travel to Europe for the clay and grass season to get away from it all. Now, Stephens says she's more comfortable with all the questions that come with being one of America's top players. As for looking for "The Next Serena," though, Stephens thinks the search is premature.