23 Jan 2019; AA: Former world number one Serena Williams was knocked out in the Australian Open by seventh seed Czech Karolina Pliskova on Wednesday.
The 26-year-old Czech beat the 37-year-old American 6-4, 4-6, 7-5 to advance the semifinals. Williams missed four match points.
World number seven Pliskova will face world number four Naomi Osaka in the semifinals.
Naomi Osaka also defeated Ukrainian Elina Svitolina to advance to the semifinals in the Australian Open on Wednesday.
In women's singles at Melbourne, 21-year-old Japanese player Osaka took the game 6-4 and 6-1 against World number six Svitolina.
