Latest stat from Matt Roberts: if Swiatek loses to Sakkari, everyone in the women's final four would be in a grand slam semifinal for the first time. The only other time that has ever happened was at the 1978 Australian Open, back when many star players didn't bother making the trip. (We're already guaranteed three first-time semifinalists, which has happened only five times in the Open era.)
Meanwhile, today's two women's quarterfinals have both been minor epics. I missed Zidansek's win over Badosa - quite an upset, to my mind - but it finished 8-6 in the 3rd, and Rybakina is currently 6-6 in the third with Pavlyuchenkova. Pav has reached the quarterfinals of every slam in both singles and doubles but has never reached a semifinal in either singles or doubles; if she loses here, she'll at least get another chance in the doubles quarterfinals...with Rybakina as her partner.