WTA Chairman & CEO Stacey Allaster said the Australian Open title is a testament to Li Na's mental toughness after the Chinese superstar secured her second Grand Slam crown at the Melbourne park on Saturday.

The 31-year-old fourth seed's 7-6 (7-3), 6-0 win earned her the title on her third attempt after losing the 2011 and 2013 finals, adding to the French Open crown she won three years ago.

"On behalf of the WTA team I congratulate Li Na on her Australian Open title. As one of the extraordinary role models in women's tennis, it's great to see her achieve her goal," Allaster said through an email.

"For several years we have witnessed a strong champion get better each year and this Grand Slam title is a testament to Li's mental toughness and her relentless commitment to learn and improve her game," she added.

By claiming the title, Li became the oldest winner of the women's title in Australian Open, surpassing Margaret Court who was 30 when she became champion in 1973.