Paris (AFP) - Poland's Iga Swiatek, who will become world tennis number 1 on Monday, has pulled out of the Charleston tournament in the United States.
Swiatek scooped her third successive WTA 1000 title by beating Naomi Osaka in the Miami Open final on Saturday.
Swiatak said cumulative fatigue was on the verge of leaving her injured.
"Sorry everyone but after playing a marathon three finals I'm tired, and have a slightly injured arm," she explained.
The Polish 20-year-old became only the fourth - and youngest - player to win the "Sunshine Double" of Indian Wells and Miami in the same year following Steffi Graf, Kim Cljisters and Victoria Azarenka with a 6-4, 6-0 win over Osaka.
Swiatek, who will be formally confirmed as world number one when the new WTA rankings are announced on Monday, has now won 17 straight games, a winning streak that includes titles in Doha, Indian Wells and now Miami.