World number one Caroline Wozniacki came back from a set and 4-1 down to defeat Svetlana Kuznetsova and reach the US Open last eight on Monday just as her lofty status again looked too heavy a burden to bear.

Caroline Wozniacki celebrates winning against Svetlana Kuznetsova on
Monday. Pic/AFP

The Dane, who is still searching for an elusive Grand Slam title to support her top ranking, saw off the tiring 2004 champion Kuznetsova 6-7 (6/8), 7-5, 6-1 and will now tackle Germany's Andrea Petkovic for a place in the semis. In the other quarter-final in the top half of the draw, three-time winner Serena Williams will clash with Russia's Anastasia Pavlyuchenkova.

It was a huge struggle for the 21-year-old Wozniacki on a night of fluctuating fortunes on Arthur Ashe Stadium in a gruelling 3hr 2min. 

She surrendered a 5-2 lead in the first set tie-break and then slipped 1-4 down in the second set before 15th-seeded Kuznetsova's game fell to pieces. "I knew I could come back so I just stepped into the lines and went for my shots. I am in good shape. I can play for five hours if I have to. I wanted to keep the rallies going."