Unheralded Canadian teen knocks Wozniacki out of Auckland

18-year-old Bianca Andreescu of Canada ranked 152nd in the world beat Williams 20 years her senior and a seven-time Grand Slam winner

Overcoming a back injury and a cold, Canadian teenager Bianca Andreescu upset top-seeded Caroline Wozniacki 6-4, 6-4 Thursday and advanced to the quarterfinals of the ASB Classic.

"I can't believe it right now, " Andreescu said.

Venus Williams reacts after a point against Bianca Andreescu of Canada during their women's singles quarter-final match at the ASB Classic.

So I wouldn't mind if someone else did that, but at the end of the day you get your mind ready and you say I'm here to play tennis to perform and try your best. She came out and held, broke Wozniacki for a 5-4 lead and then served out the match on her first match point. Crucially, too, Andreescu fixed her serve, raising her first serve percentage from 51% in the first set to 69% in the second and 65% in the third.

Andreescu, 18, won 11 games in a row on her way to a 6-7 (1-7) 6-1 6-3 win over Williams at the Auckland International.

Despite struggling with various delays, including a medical timeout for a recurring back issue, cramps, rain stoppage and glitchy signage, Andreescu was able to hold her nerve to seal victory in two hours, twelve minutes after one final forehand victor.

"I think this was one of the toughest matches I've ever played and probably the toughest here in Auckland", Goerges said. "I fought and I really enjoyed myself". "But I'm still searching for perfection and she really, really, really can hit the ball".