The rising heat and humidity at the U.S. Open has prompted organizers to adopt a new policy that allows them to partially close the roofs on the main stadiums.

American Danielle Collins captured her second career title in just a two-week span, holding off No. 4 seed Daria Kasatkina of Russia 6-3, 6-7 (10), 6-1 after a thrilling second-set tiebreaker to win the Mubadala Silicon Valley Classic.

Daniil Medvedev was struggling so much with the suffocating heat and humidity in the Olympic tennis tournament that at one point the chair umpire asked him if he could continue playing.