(CNN) -- Wimbledon champion Venus Williams slumped to a shock Australian Open exit on Thursday when she succumbed 2-6 6-3 7-5 to Spain's Carla Suarez Navarro.
Spain's Suarez Navarro celebrates her victory over sixth-seeded Venus Williams at the Australian Open.
Suarez Navarro, the world number 46 and making her first appearance in the Melbourne Grand Slam event, showed few signs of nerves in their second round clash.
Second-seeded sibling Serena had earlier defeated Argentine Gisela Dulko 6-3 7-5 and 2008 quarterfinalist Venus also appeared to be on course for a straight sets win.
Sixth seed Venus was in complete control in the 29-minute opening set, breaking her rookie rival in the first and fifth games, but Suarez Navarro swept into a 3-0 lead in the second when the American's concentration appeared to waver.
Venus, 28, recovered to 4-3 but then lost her own service to give Suarez Navarro the opportunity to level the match.
Williams took early control in the decider but failed to convert a match point against the serve at 5-4 -- and ended up losing the final three games.
"When you go on court you have got to expect anything," Venus told the UK Press Association. "I'm not surprised at how well she played. I haven't quite figured out the areas of my game that went wrong, but I have to credit her."
Swiss 14th seed Patty Schnyder also went out, beaten 6-3 6-1 by Frenchwoman Virginie Razzano while Serena Williams was not too happy with a performance that saw her trailing 5-2 in the second set. Serena reeled off five games in a row to reach the third round but later rated her showing "a D-minus at best."
There was also a scare for the 2006 champion and 20th seed Amelie Mauresmo of France who lost her opening set against British qualifier Elena Baltacha before progressing 4-6 6-3 6-2.