Caroline Wozniacki used her aggressive groundstroke game to near perfection yesterday and pummeled Italy’s Sara Errani 6-0 6-1 to reach the semis of the US Open.

The 10th seed reached the last four at a grand slam for the first time since 2011 by beating Errani at her own strategy, engaging in long baseline rallies but using superior power to open the court and find lanes for winners.

Dane Wozniacki walloped winners of all varieties, belting 26 of them to just 12 for her Italian opponent, who looked dazed and confused at times on court.

The match ended when an Errani forehand hit the net tape and flopped back on her own side of the net and the strains of “Sweet Caroline” began to serenade Wozniacki over the loudspeaker.

“It’s been a pretty up and down year for me,” said Wozniacki, whose two-year relationship with world number one golfer Rory McIlroy ended this year just days after their wedding invitations were sent out.

“To be here in the semis of the US Open once again is an incredible feeling... hard work pays off.

“I’m here and I’m so happy.”

Standing in her path to a return to a slam final is China’s unseeded Peng Shuai, who was impressive in routing Swiss Belinda Bencic 6-2 6-1 in the lower half of the women’s draw where the leading seeds have vanished in upsets.

Women’s QFs: Makarova bt Aza-renka 6-4 6-2.