World No. 1 Aryna Sabalenka staged a dramatic comeback to defeat 20-year-old qualifier Nikola Bartunkova and advance to the semifinals of the Berlin Open on Friday, June 19. After trailing by a set and 4-0, Sabalenka fought back to win 2-6, 7-6(2), 6-4 in a match lasting two hours and 22 minutes.