The 18-year-old Canadian battled back to beat the former world No. 1 6-7 (1), 6-1, 6-3.
AUCKLAND, New Zealand — Canadian teenager Bianca Andreescu knocked off another former No. 1 on Friday, beating seven-time Grand Slam champion Venus Williams 6-7 (1) 6-1, 6-3 to reach the semifinals at the ASB Classic.
The 18-year-old Andreescu, who is ranked 152nd in the world and had to go through qualifying to make the tournament, defeated top-seeded Caroline Wozniacki in the second round.
''I believe that anything is possible and tonight I think I did the impossible,'' Andreescu said. ''My goal was only to qualify and maybe get a couple of rounds in but now I beat a couple of top players so who knows? I believed in myself to the end. I fought and I really enjoyed myself.''
After being broken in the opening game of the second set, Andreescu reeled off 11 straight games to take control of the match.
Also, defending champion Julia Goerges saved a match point in the third set before beating Eugenie Bouchard 3-6, 6-3, 7-6 (6).
Playing with a swirling wind that made serving difficult for both players, Goerges hit seven aces and 47 winners.
''I think this was one of the toughest matches I've ever played and probably the toughest here in Auckland,'' Goerges said. ''The winds today were swirling around, coming suddenly and then gone.
''Chairs were flying around, hats, everything. But you can't do anything about it, you just have to accept it and stay positive about it.''
Bouchard held a match point on serve at 6-5 in the final set but couldn't convert.
Viktoria Kuzmova reached the semifinals by beating American teen Amanda Anisimova 6-3, 2-6, 6-4. At 17, Anisimova is the youngest player in the top 100.