Angelique Kerber climaxed a dream season at the US Open on Saturday, performing as the champion she has become through hard work, patience and a love of the game.

Kerber wiped tears of joy and relief from her eyes before accepting a winner's cheque for $3.5mn and a gleaming silver trophy after fighting back to beat Karolina Pliskova in a display worthy of the new number one player in women's tennis.

The 28-year-old German second seed will become the oldest player to rise to that rank when the new list is published on Monday but Kerber can wait, as her patient climb to the top has proven.

Kerber took up tennis at age three, but did not win her first significant junior title until she was 15.

She turned professional and another dozen years passed before her first grand slam title at this year's Australian Open. Eight months later brought her to world number one.

Kerber finished last year ranked 10th in the world and turned dreams into a reality this year after rededicating herself.

"I was really trying to improve a lot of things," she explained following her 6-3 4-6 6-4 triumph after falling a break down in the third set.

"First of all, my fitness and then to being more aggressive and go for it when I have the chance. Not just hitting the balls over the net.

"And also, mentally, to being more positive, a little bit more stronger, and just focusing on the moment I am on court."

Left-hander Kerber used to get down on herself when mistakes piled up. It showed in her body language and in her results.

"I was always dreaming to being number one and to be in the grand slams," she said. "Now to see that the work pays off, this is actually the best feeling."

Kerber said improving her fitness laid the foundation.

"I'm really trying to play more intense when I practice ... and spending a lot of hours as well in the gym or just making a lot of sprints and movement.

"I felt this was one of the biggest things, when you know you can run forever on court and you're not worried that you can play three sets. I think this is really important for your confidence and you can go for it."

Long regarded as a top defensive player, Kerber reaped the benefits of her makeover in the very first major of the year, reaching the Australian Open final and beating Serena Williams for her maiden major.

She was runner-up to Williams again at Wimbledon, and claimed silver at the Rio Olympics.

Kerber said if you believe in your fitness, you believe in yourself. "That gives you a lot of confidence when you know you work very hard.

"It was just the next step to beat the best players."

Kerber said she turned aggressive and took her chance at a critical moment against Pliskova after breaking the Czech back to level the third set 3-3.

She finished the match by winning the last eight points, breaking Pliskova at love.

Kerber said the enormity of winning her second slam of the year and attaining world number one would probably not sink in until a quiet moment after she boarded her flight home.

She was asked about the lessons of her journey.

"You have to believe in your dreams. You have to go with a lot of patience," she said.

Asked what she might pass on to her children one day about achieving their dreams, Kerber said. "I think I will show a few videos to my children in a few years.

"And I don't know, just tell them, just believe in yourself and do what you really love."