China's Wang Qiang celebrates winning her first round match against Sloane Stephens of the US at the Australian Open tennis tournament at Melbourne Park, Australia, January 18, 2016. [Photo/Agencies]

MELBOURNE - Chinese qualifier Wang Qiang has scored a sensational opening round win over American Sloane Stephens on Day 1 of the Australian Open.

Wang knocked out Stephens, an AO semi-finalist three years ago, in straight sets 6-3, 6-3 in one of the biggest upsets of the opening day.

Despite being ranked 76 spots below Stephens, Wang controlled the game from the baseline and quickly went a set up.

The qualifier then broke in the first game of the second set, and broke Stephens another two times to close out the match. Wang became just the second player, in the women's draw, to knock out a seeded player to date, with Russian Margarita Gasparyan beating 17-seed Sara Errani.

The 24-year-old was ecstatic after progressing to the second round, labelling the win the best of her career.

"(Stephens) is a good player ... I just tried my best," Wang told reporters after the match.

"It was my first time playing at Hisense (Arena), so (I was) a little bit nervous."

Wang was left blushing after a reporter compared her impressive forehand action to two-time Grand Slam champion, and compatriot, Li Na.

Stephens wasn't so jovial when she spoke to reporters following her early exit, but credited Wang and suggested her challenger's lead-up form may have proved the difference.

"She's played all this week, three solid matches," Stephens, 22, told reporters on Monday.

"She played a really good match and I wish her well in the future."