2 – Polish women in the second week after Magda Linette joined Swiatek with a 6-3, 6-4 defeat of No.19 seed Ekaterina Alexandrova in the last third-round match to be completed.The only previous Grand Slam last-16 lineup in the Open Era that featured two Polish women was the 2008 Australian Open, when Agnieszka Radwanska reached the quarterfinals and Marta Domachowska the fourth round.
https://www.wtatennis.com/news/3030784/aussie-open-day-6-by-the-numbers-breaking-down-the-last-16