The Dane ground out the first set against Flavia Pennetta, taking it 7-5, before storming to a second-set 6-0 whitewash.
The third seed’s reward is a last-four match-up with the top-ranked Simona Halep, who got through by beating Ekaterina Makarova in three sets.
Romanian Halep won the first set to three games, but folded in the second to lose it to one. She recovered, though, and took the match 6-3 1-6 7-5.
Earlier in the day Garbine Muguruza shaded the battle of the Spaniards as she beat Carla Suarez Navarro across three sets.
Suarez Navarro won the opener on a tie-break to four, but Muguruza responded to win the next two sets 6-3 and progress.
The other quarter final saw another comeback as Karolina Pliskova lost the first set to Lucie Safarova 6-3 but took the remaining ones 7-6 (7/5) 6-1 to go through.
Muguruza and Pliskova will open the play on Friday.