They have played eight times since 2008 Agnieszka has lost the lot, taking just one set along the way.
If you were among the packed Centre Court crowd, you might not have noticed that cheering him on was former Wimbledon Ladies champion, Maria Sharapova, Dimitrov's girlfriend.
Although the Russian beat Williams in the 2004 Wimbledon final, but Williams has won their past 13 matches in a row, including in the French Open final two weeks ago, the report added.
Grigor Dimitrov might have been playing his first Wimbledon semi-final, but it appeared that the BBC were more interested in his girlfriend.
Last week, Maria Sharapova and the Spanish model Andrés Velencoso were in Paris for marketing reasons (Masha for her candy brand, Sugarpova), and decided to spend a little time together.
Velencoso split with the 26-year old actor Ursula Corberò at the end of 2015, while Masha split with Dimitrov almost a year ago. Looking at the following photos (taken by Hola Magazine), it looks like it is...