Teodora Kostovic brushed off Aryna Sabalenka’s level after losing to the world No. 1 in the Wimbledon first round. The 19-year-old Serb said Sabalenka’s tennis is not “out of this world” and backed herself to win their next meeting. It is another sign of the confidence driving Kostovic’s rise, with comparisons to Jelena Jankovic and Ana Ivanovic already following her.