Believe it? Kerber would not have only two weeks ago when she faced a match point in the first round. Doubt it? Kerber would have been entitled to, after admitting she lost her nerve against Lucie Safarova at the WTA Finals last October in Singapore, then vowing that it would not happen again.

The 28-year-old had beaten Williams before, just the once, but it was enough to give her the confidence she could do it again. Kerber had, after all, eliminated tournament second favourite Victoria Azarenka in the quarter-finals. She was a finalist in Brisbane. Everything was coming together, falling into place.

"I was trying to believe much more in myself. When I won the first set, when I won against (Victoria) Azarenka, that shows me that I really am a good player and I can show it as well on the big courts. You know, I was not playing very good last year on the big tournaments. This is the first big tournament of the year, and I won it, the first grand slam."

Sounds crazy, even to Kerber, who admitted she had played like someone with nothing to lose after coming so close to it on day two, and also with less pressure than an opponent seeking to make history. The fact Williams could not quite manage it leaves 22-time major winner Steffi Graf's Open era record safe for the moment.

"Yeah, I think I helped Steffi right now. I mean, yeah, Steffi is a champion. She won 22 grand slams. That's my first one," said Kerber, Germany's new world No. 2. "I'm really happy about my game I played. The hard work pays off.

"You know, I really try to improve my game, improve also my mentality, to stay more relaxed. That it works everything here in these two weeks is just amazing."

Kerber had started strongly and played well in the first set; Williams better in the second. She grabbed the early break in the third, but the big game was at 3-2, which will be remembered for two brave and perfectly executed drop shots. Kerber led 5-2, served for it at 5-3, finally clinched it at 5-4, when another Williams forehand volley sailed long.

"When I hit the match point, I was just try to hoping to return the ball over the net. Just hoping, yeah, that I can make the ball and just going for it if I have the chance," Kerber said. "Yeah, when the ball was out from her, I was just, yeah, so happy. I mean, it's amazing."

And, while unaware of Williams' fine record in three-set grand slam finals, she was confident of her own ability to go the distance in her first. Her ambitions now? "To win some more," she beamed.

"Right now I'm not thinking about this. I try to really enjoy every moment, what's happened right now, taking all the experience with me. I mean, I think my phone is exploding right now. I don't know how many messages I get. It's like amazing.

"I think it's so good also for Germany, for the German tennis. After Steffi, now somebody won a grand slam. It's like just amazing. Right now I'm not thinking about the next tournaments, the next challenges. I'm just trying to stay here and enjoy everything."

It is one thing to get to a winning position, but another to finish it off, and this, said the seventh seed, was a victory for the believers - notably her family and team.

The toughest time was in 2011, when she lost 11 times in first rounds. Then came the US Open semi-final that altered everything; Saturday's was the match that will transform her even more.

"Sometimes I was not believing too much in myself. Here it's changed everything," said Kerber. "My coaches and everybody, they saw that I played very good in the practice. They couldn't understand actually why I can't transfer it to the matches.

"That's why I think that I am not the easiest one to coach or to say something that it works. I think now I find my best team and they can handle me."

That includes long-time coach Torben Beltz, a likeable character who returned to Team Kerber last year after an 18-month split, and was celebrating a great final, and even better result.

"I think it was a high level final - that's what I thought, because I had the Angie-glasses on maybe, I'm not sure," Beltz laughed.

"I think she believed in it, I think she believed she could win the match and she did."