Melbourne, Jan 31 (IANS): Germany's Angelique Kerber stunned six-time Australian Open winner Serena Williams 6-4, 3-6, 6-4 to win her maiden Grand Slam title at Melbourne Park here on Saturday.

Starting the match as a rank outsider, the seventh seed was in crushing form throughout her first Grand Slam final, extending the rallies, forcing Williams to the net and showing no sign of nerves as she denied the World No.1 a record-equalling 22nd Grand Slam win, reports Xinhua.

The German, who was matchpoint down against Misaki Doi in her first round match two weeks ago, is the first woman to win a Grand Slam after having faced a first round matchpoint. She is also the first German woman to win a Slam since the turn of the century.

But it wasn't smooth sailing early for the Major final debutant. Both women displayed nerves early in the encounter, but it was plainly evident in Kerber's first service game of the match; she double faulted once and missed a number of relatively slow first serves.

Despite the shaky start, Williams too was on edge and the German managed to hold. What followed was polar opposite of the first five minutes.

Williams, who said after the final that she was a little nervous, unable to forge momentum early in the first set, going down the first break of serve to Kerber who worked angles brilliantly and displayed vintage defensive tennis - something that couldn't have been further away from what she dished up in the opening game.

Meanwhile, the World No.1 was uncharacteristically off with her shot selection, hitting 23 unforced errors throughout a disastrous first set. In comparison, Williams hit 20 unforced errors for the entire match against both Agnieszka Radwanska and Maria Sharapova earlier in the tournament.

While Kerber took full advantage of the No.1 seed's slow start to the first, Williams managed to get her feet moving and her shot selection right in the second. The pressure almost looked too much for Kerber at times - a wayward ball toss on second serve was punished more than once as Williams regained control of the match, hitting only five unforced errors in the set compared to Kerber's seven.

The third set was the most testing for both competitors with Williams struggling to hit a first serve - meaning Kerber could force Williams wide and deep after returning lacklustre second serves from the six-time champion.

But Kerber herself had issues closing out the match. Up a break and a hold at 5-2, the German allowed the American to claw her way back to 4-5, breaking back in the process, which allowed Williams to serve to level the match.

But in what was another twist in a modern classic, Kerber broke Serena's serve once again, taking advantage of her first and only championship point to close out the match in a gruelling two hours and eight minutes.

The 28-year-old said she went into the match with a plan to stay aggressive and work Williams' weaknesses.

"When I went on court I was telling myself I have the chance if I go for it. I had to play aggressive against her. I played really well in the first set," Kerber said.

At 5-2 up in the third, it looked to be a formality for Kerber, but the 21-time Grand Slam champion managed to force a break and then display a strong hold to threaten a late revival.

"When I was 5-2 up, I had too many things in my mind. On matchpoint I was just trying to return and focus on the moment," Kerber said.

Meanwhile, Williams said playing a left-hander for the first time in more than five months could have thrown her off her game.

"It was a really intense match. It's tricky playing a lefty too - there is different spin and different shots you have to get used to. I was missing a lot of the ground strokes and when I came to the net. I kept picking the wrong shots. It's something to learn from and try and get better. I did the best I could. Would I give myself an A? No, but this was what I could produce," Williams said.

Williams, the heavy favourite before the match, said she might have subconsciously felt the pressure that fans, the media and the tour put on her to win Grand Slam tournaments.

"(The media) expects me to win every match, but I'm not a robot. I try to win every single time but realistically I can't do it and I wasn't able to do it tonight," she said.

With the breakthrough Grand Slam win, Kerber will move to No.2 in the world when revised rankings are released next week.

The Australian Open will conclude in Melbourne on Sunday evening with defending champion Novak Djokovic playing Brit Andy Murray in the men's final.