Serena Williams says she might have died if not for her trainer, Esther Lee, demanding that she go to the hospital when she developed a blood clot in February 2001.

“I didn’t want to go and she told me you got to go, and that was the beginning of stuff that was really bad but ended up being good for me," Serena told a small group of reporters. "I’ve thanked her so many times for that because it literally could have been life changing."

Serena added that she didn’t tell her mother Oracene Price what happened because she didn’t want her to see that she was afraid.

"She didn’t tell me," Oracene said. "I was pretty upset because, what if something had really happened? I already lost one kid. She really pissed me off."

Oracene’s daughter, Yetunde Price was murdered in Los Angeles in 2003.