But Anisimova hit back with a break of her own and led 0-40 with Halep serving for the match, only for the Romanian to win the next five points in a row, claiming the victory when Anisimova drifted a backhand long.
It means Halep is still yet to drop a set at this year’s tournament and is well-placed to win her third grand slam title and second at Wimbledon.
“Definitely, I’ve played the best tennis (since 2019),” she said in her on-court interview. “I struggled a lot last year and now I’m just trying to build my confidence back.
“(My) tennis is here, so I just have to believe. I’ve started to do that and it feels good.”
Halep will next face Kazakhstan’s Elena Rybakina after the 17th seed’s 4-6 6-2 6-3 comeback win against Australia’s Ajla Tomljanović in the other women’s semifinal on Wednesday.
“It’s great to be back in the semifinals,” Halep added. “I’m very emotional right now because it means a lot to be back in the semis. I played a tough opponent today, she could crush the ball in the end.
“I didn’t know actually what to do, but I just believed in myself, I said I have to stay there strong on my legs — they helped me today — and I believed till the end that I can win.”
Halep raced into a 5-1 lead against Anisimova as she broke her opponent at 1-1 and 3-1 before taking then first set in 30 minutes.
Anisimova lost her radar in the second set and ended the match with 28 unforced errors to Halep’s six.
The contest looked to be out of reach for the 20-year-old American at 5-1 in the second set, but Anisimova started producing the big shots she had been searching for earlier in the match and came close to leveling the set at 5-4.
The late surge was too late, however, and Halep rallied to reach her third Wimbledon semifinal.