(Miami) Iga Swiatek withdrew from the Miami Tennis Open on Wednesday due to a rib injury.
Swiatek, the defending champion and ranked number one in the world, was scheduled to face Claire Liu in the second round on Thursday.
As the top seed, three-time Grand Slam champion Swiatek enjoyed a bye to the first round of the hard-court tournament she won a year ago in a streak of 37 unbeaten matches.
It was the longest such streak in women’s tennis in a quarter of a century.
Swiatek, 21, from Poland, said after losing 6-2, 6-2 to eventual champion Elena Rybakina in the BNP Paribas Open semi-finals on Friday that her rib bothered her.
“I have to take more tests and see what happens. I don’t know yet,” Swiatek said on Friday.
Instead of playing Swiatek, Liu will face 94th-ranked Julia Grabher, who lost in qualifying but can now enter the main draw as a “fortunate loser”.