Ash Barty's classy act of generosity after record windfall

She's effectively won lotto six times in one week, but low-maintenance tennis superstar Ashleigh Barty only plans on splashing out on her niece and nephew following her historic pay day in China.

Australian sport's new six-million-dollar girl promises fortune and fame won't change her after squirrelling away the biggest cheque in tennis history with her WTA Finals success in Shenzhen.

Barty pocketed $6.4 million for crowning her triumphant season with a 6-4 6-3 victory over defending champion Elina Svitolina on Sunday night.

No player - not even Roger Federer, Rafael Nadal or Serena Williams - has ever received such riches from a single tournament.

Ash Barty reacts to her record-breaking WTA Finals victory. Pic: Getty

But Barty declared "I've got everything that I need" before revealing her plans to spoil three-year-old niece Lucy and near-two-year-old nephew Oscar.

"Thankfully they can't read but for Christmas they're getting a new swing set, which they're pretty excited about now that they've got the trampoline and swing set out the back," the humble champion told AAP in Shenzhen.

"And I know Luce and Oscar are very keen to learn how to play tennis so I think that's going to be pretty special to try and get a racquet in their hand. They already run around with a racquet, it's amazing.

"So, look, I mean the amount of zeros you have in the bank account doesn't change how I'm going to spend my off-season and spend time with my family.

"Because that's one of the biggest times that I miss throughout the year, is spending genuine time with them.

Barty thrilled with ‘incredible’ achievement

"It's great that I can buy them things that they love but I live a pretty simple life. I'm not living an extravagant life.

"I'm pretty happy in my little house at home. I've got everything that I need. I'm pretty boring. I don't really spend a lot on myself."

If she did, Barty could certainly shop high end.

Ash Barty holds the WTA Finals trophy aloft. Pic: Getty

Her unprecedented pay day for a professional tennis player - man or woman - took Barty's 2019 prize money haul to $16.37 million.

That's more than men's world No.1 Novak Djokovic, who has so far amassed $16.06 million ahead of the men's season-ending showpiece in London.

"It's incredible; we're breaking records this week in particular, putting tennis on the map, putting WTA tennis on the map," Barty said.

"I feel like we've earned that right to be recognised more as a global sport."