The "mild and sunny weather" Tokyo's bid for the Summer Olympics promised in 2013 was nowhere to be seen on the first day of the Tokyo Olympic tennis competition.

Actually, there was plenty of sun on Saturday at Ariake Tennis Park, but few would classify the weather as mild.

"It's different," Poland's Iga Swiatek said after her 6-2, 6-2 win over German Mona Barthel. "It's humid. In some places in the States it was probably similar, but still, I'm not used to it."