Serena Williams came within two points of defeat before beating a spirited Shahar Peer of Israel in an enthralling Australian Open quarter-final.
Williams won the women's title in 2003 and 2005
Two-time champion Williams was flat in the first set and Peer took advantage.
Williams battled back, winning eight out of nine games from 2-2 in the second set to seemingly take control.
But 16th seed Peer showed great resolve to fight back in the final set and even served for the match before a fired-up Williams finally won 3-6 6-2 8-6.
It is the second time in the tournament that American Williams has flirted with defeat after Nadia Petrova also served for the match against her in the third round.
I think I came out a little flat, started out a little slow. Maybe I was just a little nervous
The 25-year-old was pumped up in the second and third sets and was visibly delighted after clinching a victory which took two hours and 34 minutes.
"I wasn't playing my best tennis, I'm excited I was able to come through," she said. "I am the ultimate competitor."
Williams, champion here in 2003 and 2005 but unseeded this year after spending much of last season out with injury, was broken in the first game of the match and looked lethargic and out of sorts in the opening set.
But she rallied herself in the second set and broke twice to level the match.
At that stage she looked set for victory but Peer, playing in her first Grand Slam quarter-final had other ideas.
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The 19-year-old clawed her way back into contention in a hard-fought opening to the third set, in which the first four games took 34 minutes to complete.
Williams had to save break points in the first and third games and then broke Peer in the fourth game.
Again Peer refused to lie down and broke back in the ninth game and another break in the 11th left her serving for the match.
However, seven-time Grand Slam champion Williams showed real grit and desire to break back and then clinched victory on her first match point when Peer floated a backhand wide.
Williams now meets Czech 10th seed Nicole Vaidisova for a place in Saturday's final.
"I don't think I played as strongly (as against Jelena Jankovic in the last round)," said Williams.
"I think I came out a little flat, started out a little slow. Maybe I was just a little nervous. I didn't have enough blood pressure in my feet.
"I just had to get going. I had to work my way in the match."