But Anisimova hit back with a break of her own to lead 40-0, with Halep serving for the match, only for the Romanian to grab the next five straight points and claim the win when Anisimova drifted a long backhand.
It means Halep is yet to drop a set at this year’s tournament and is well positioned 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 trying to get my confidence back.
“(My) tennis is here, so I just have to believe. I started it and it feels good.”
Halep next meets Elena Rybakina of Kazakhstan after the 17th seed’s 4-6, 6-2, 6-3 comeback win over Australia’s Ajla Tomljanović in Wednesday’s other women’s semifinals.
“It’s great to be back in the semifinals,” added Halep. “I’m very emotional right now because it means a lot to me to be in the semifinals again. I played against a strong opponent today, she could crush the ball at the end.
“I didn’t really know what to do, but I just believed in myself. I said I have to stay strong on my feet – they helped me today – and I believed to the end that I could win.”
Halep went 5-1 up against Anisimova as she broke her opponent 1-1 3-1 before winning the opener in 30 minutes.
Anisimova lost her radar in the second set, ending the match with 28 unforced errors to Halep’s six.
The competition seemed out of reach for the 20-year-old American going 5-1 in the second set, but Anisimova started producing the big shots she was looking for early in the game and nearly leveled the set to 5-4 .
However, the late surge was too late, and Halep rallied to reach her third Wimbledon semi-final.