Jelena Ostapenko felt a surprisingly slow Centre Court gave Angelique Kerber the upper hand in their Wimbledon semi-final on Thursday.

Kerber triumphed 6-3 6-3 against the 2016 French Open champion and will face Serena Williams in a repeat of their final meeting two years ago.

The typically gung-ho Ostapenko hit 30 winners to just 10 from the resilient German but committed 29 more unforced errors to exit at the final four.

The Latvian, whose only previous outing on Centre Court this year was a first-round win over Katy Dunne, was unimpressed by the standard of the surface, which she felt aided Kerber.

Ostapenko told a news conference: "I think the Centre Court is much slower than the other courts I played before. I think she had really many advantages because of that. My shots were not that effective on such a slow court.

"But in general, I think she was defending quite well. She was also serving quite good today.

"I played only one match on Centre Court, and I didn't actually expect it was that slow.

"Last year was a little bit different conditions because the roof was closed. Everything was faster.

"But this year the roof was opened. I felt like when I played, for example, on Court 3, 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."

Despite her rankles with conditions on Centre Court, Ostapenko acknowledged a need to be more reliable in her shot-making.

"I think I have to play very consistent. On this level, if I'm doing so many unforced errors, it's not going to work. Players like Angie, she's very consistent. If I want to play on that level, I have to reduce my unforced errors," she said.

"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. But in practice, of course, I'm working on longer rallies and in general on that."