WIMBLEDON, England—Simona Halep says nerves were the reason for her first-round exit at Wimbledon, where she reached the semifinals a year ago.

The world No. 3 lost in three sets to Jana Cepelova despite winning the first set. The Romanian has won three titles this year, including Indian Wells. She fell in the quarterfinals at Birmingham before withdrawing from Eastbourne after having a title-less clay-court season and losing in the second round of the French Open.

Those defeats affected her confidence, Halep said, but her performance was still below what she anticipated.

"My confidence wasn't too high. So I knew that during the matches it's difficult because you feel the pressure," she said following the match. "I knew it would be difficult, but not like today, to be honest.

"I wasn't there. I couldn't handle it very well. She came back in a good way with her game. She was pushing me a lot. She was aggressive. But I can say that I let her come in and play aggressive."

Halep now plans to take a vacation, then begin training for the hardcourt season.

Following her defeat at the French Open, the 23-year-old criticized her game, saying she was trying to hit too hard. This time, she was satisfied with her approach, but wants to improve emotionally.

"Actually about my game, I have no bad things. I'm confident in my game. But emotional and, like, inside power, it's not there," she said. "My game is there... I'm a little bit nervous when I have to finish the match. So like today I won first set. In Birmingham as well I won first set, then I couldn't win."

She insisted that changing coaches just before the tournament has not affected her.

"I want to go on court and say, I don't care what I'm doing, just to go play tennis. It will come soon. I believe and I have this confidence," she said. "It's just about emotional.

"I will speak with my team, with my people who are around me. I have good people and I'm happy with this. Yeah, I don't believe that it's so difficult to come back... " she sad.

Halep is 32-8 for the season.