Lisa Raymond provided the biggest shock of the Australian Open so far by knocking out third seed Venus Williams in straight sets.
Williams, playing her first tournament for over six months, was well below par throughout, committing a total of 44 unforced errors.
But Raymond kept her nerve brilliantly against last year's finalist to emerge a 6-4 7-6 (7-5) winner.
Raymond had never won a set against Williams in three previous encounters.
"I couldn't ask anything more of myself today," said a delighted Raymond.
"I think I played an incredible match.
"It's pretty difficult to play someone who is serving like that today. I came into this match knowing I had to step up to the plate and go for it - it's the only way I was going to win."
Raymond also revealed that she felt inspired after receiving a text message from doubles partner Martina Navratilova that read "Just be brave".
Williams served 14 aces and managed 40 winners but despite fighting back from a break down to force a second-set tiebreak, she was unable to raise herself to force a decider.
"I'm pretty much in shock," said Williams after her worst Grand Slam performance since losing in the first round of the 2001 French Open.
"I still can't believe it. That's the way I feel after every loss. But that's the way it goes, you win some, you lose some."