Early in the film Richard Williams states that in 1977 he only earned $52,000 as if that was a small amount of money. In today's dollars (2022) that would be the equivalent of at least $250,000 per year, hardly poverty wages.
Arantxa Sánchez Vicario is regularly announced and shown as Vicario on the scoreboard, which wouldn't have happened. She was first known as Arantxa Sánchez, then she added Vicario to honor her mother. Following Spanish usage, Sánchez, her father's name, was always the prime part of her last name and she was known as Sánchez Vicario.
In 1994 the number 1 in the WTA ranking was Steffi Graf, while Arantxa Sánchez Vicario was actually number 2.
In her match against Stafford, Venus is serving in the 3rd game of the match but receiving serve in the 5th game. These games would have the same server.
When Serena "secretly" signs up to play in the same Juniors tournament that Venus has enrolled in, she is assigned to play on Court #9 . . . just after Venus was sent to Court #10. Those courts the same fenced enclosure (as an image of Courts 11-12, indicates), so the surprise of Serena playing in the tournament would be short.
Venus Williams & Arantxa Sánchez Vicario are showing playing the 1994 Bank of the West Classic on a blue tennis court. The United States Tennis Association did not start using blue tennis courts until 2005.
During the opening credits, the Williams neighborhood in the late 1980s is shown, complete with vintage cars and clothing. However, also shown is an early 2000s white Toyota Sequoia.