Misfiring Ostapenko blames 'slow' Centre Court

LONDON, July 12 (Reuters) - Jelena Ostapenko blamed a 'slow' Centre Court after her power game misfired against Germany's Angelique Kerber on Thursday.

The 21-year-old had not dropped a set on her way to becoming the first Latvian woman to reach the Wimbledon semis, but self-destructed against Kerber in an error-strewn 6-3 6-3 defeat.

Ostapenko, who blazed away to win the French Open last year, still delivered 30 winners, but was guilty of over-pushing at times against the resolute left-hander.

"I think the Centre Court is much slower than the other courts I played on before," the 12th seed said.

"I think she had really many advantages because of that. My shots were not that effective on such a slow court."

Ostapenko's previous experience of playing on Centre Court was last year against Venus Williams in the quarter-finals.

"Last year was a little bit different conditions because the roof was closed. Everything was faster. For Venus it was a big advantage last year," she said.

"But this year the roof was opened. I felt like when I played on Court Three, for example, the shots I was hitting were more effective than the shots I was hitting today.

"I was hitting many good balls, but she was getting everything back. I felt like the court is really slow."

Ostapenko made 36 unforced errors on Thursday as she failed to find a happy medium between attack and staying patient.

When her big bombs did hit the mark they drew gasps from the crowd -- but they were few and far between.

"Ostapenko still goes big even when she is having trouble with so many unforced errors," twice U.S. Open champion Tracy Austin said in summarising for the BBC.

Ostapenko acknowledged that she must, on occasions, try to reign in her natural instincts.

"At this level, if I'm doing so many unforced errors, it's not going to work. Players like Angie, she's very consistent," Ostapenko, who lost in the opening round at the French Open as defending champion, said.

"If I want to play on that level, I have to reduce my unforced errors. Of course I'm working on my consistency.

"It's not like I want to hit every ball so hard. Sometimes in the match that happens because I really want to hit a winner, I want to win the point."

After the trauma of Paris where she became only the sixth female Grand Slam champion to fall at the first hurdle of her defence when losing to Kateryna Kozlova, her Wimbledon run was an admirable response.

"There were a lot of emotions flying through Ostapenko's body. The upside for the future seems tremendous," former men's number one John McEnroe told the BBC.

"She knows she needs to work on other parts of her game. She'll be all the better for this." (Reporting by Martyn Herman; editing by Clare Lovell)