And the 10th seed will be a big favourite to reach the final when she takes on unseeded Chinese player Peng Shuai in the last four.

Wozniacki reached the only slam final of her career in New York in 2009, losing to Kim Clijsters, and is through to the last four at one of the big four tournaments for the first time in three years.

Errani beat Venus Williams in round three and things might have been different had she taken one of four break points in the first game.

But Wozniacki saved them all and thereafter played a near perfect match, mixing aggression with control and seizing on Errani’s weak serve at every opportunity.

The Italian did not hold serve once in the match but did at least manage to break the Wozniacki serve at the start of the second set.

Normal service was soon resumed, though, and it was a sign of how good Wozniacki is feeling about her game that a player known for her defensive capabilities hit 26 winners.

The 24-year-old said: “It was a great match. It was really tricky conditions with the wind but I stayed aggressive and it really paid off today. The first game was very important. I was a little bit nervous but I served really well after that.

“To be in the semi-finals means so much to me. It’s been an up and down year but it’s an incredible feeling and it shows that hard work pays off.”

Wozniacki has beaten Peng in five of their six previous meetings but the Chinese woman was equally impressive in a comprehensive victory over Belinda Bencic earlier.

“She’s been on tour for so long,” said Wozniacki. “She’s very aggressive so it’s not going to be easy but I’m so happy to be in the semis and having another chance to be here.”