(CNN) -- Serena Williams' much anticipated clash with Maria Sharapova at the French Open won't happen after all, with Williams pulling out because of an arm injury.
The 23-time grand slam winner had played herself into form through three rounds in her grand slam comeback, but she took to the main Philippe-Chatrier court Monday to let the crowd know she couldn't compete.
Williams said she couldn't physically serve with the pectorl injury, adding she felt the injury during her third-round singles match against Julia Goerges.
The US star will have an MRI scan on Tuesday.
The French Open marked Williams' third tournament of 2018 -- and first since March -- after she gave birth to daughter Olympia in September. None of those tournaments came on clay.
It means Sharapova, who held a 2-19 record against Williams and last beat her 14 years ago, moves into the quarterfinals against either Garbine Muguruza or Lesia Tsurenko.
This story is developing and will be updated when more information is made available.