Sebastian Korda stunned two-time losing finalist Daniil Medvedev at the Australian Open on Friday, adding the Russian to a growing list of top seeds crashing out early.

The 31st-ranked American, son of 1998 Australian Open champion Petr Korda, blasted past the seventh seed 7-6 (9/7), 6-3, 7-6 (7/4) at the Rod Laver Arena to race into the last 16.

Korda's upset teed up a clash with Polish 10th seed Hubert Hurkacz – who battled past Canada's Denis Shapovalov 7-6 (7/3), 6-4, 1-6, 4-6, 6-3 – for a place in the quarter-finals.

"An unbelievable match, I sort of knew what I had to do and I stuck with it even when I was going up and down with the emotions," said the 22-year-old Korda, adding that his game plan was "just go for it".

"I'm thrilled right now, I played amazing."

Medvedev was a losing finalist at the last two Australian Opens, to Novak Djokovic in 2021 and then in a demoralising five-set defeat 12 months ago against Rafael Nadal after leading by two sets.

He was attempting to become only the fourth man in the Open era to reach three consecutive Melbourne Park finals after Djokovic, Mats Wilander and Ivan Lendl.

But that quest is now over as he joined defending champion Nadal, second seed Casper Ruud and eighth seed Taylor Fritz as high-profile first-week casualties at the season-opening Grand Slam.

Djokovic remains in the hunt for a 10th title, but has a hamstring injury and confessed on Thursday he was "worried" it could derail his tournament.

Korda displayed his credentials when he pushed Djokovic to the brink in the Adelaide International final this month, earning a championship point before the Serb rallied to win in three close sets.

The Florida native bounced back to claim a pair of victories in Melbourne against Cristian Garin and Yosuke Watanuki before meeting former world number one Medvedev. (AFP)