(CNN)US tennis star Jessica Pegula says her sister, Kelly, saved their mom's life after she went into cardiac arrest at her home last year.
In an article published in The Players' Tribune on Tuesday, Pegula opened up about her family's "tough" year which culminated in "some bizarre, messed-up, full circle moment" when Damar Hamlin suffered a cardiac arrest on the pitch during an NFL game.
In June last year, reports emerged regarding Pegula's mom, Kim -- a co-owner of the NFL's Buffalo Bills and the National Hockey League's Buffalo Sabres -- being hospitalized.
Not much was known about her condition at the time but Pegula, in her recent article, wrote in detail about what happened and how her mom has been recovering ever since.
"My mom was asleep when my dad woke up to her going into cardiac arrest and she was unresponsive for quite a while," Pegula said.
"My sister gave her CPR until the ambulance arrived. She saved her life. Even though she doesn't like to take credit for this terrible situation, she absolutely saved her life, followed by the critical job performed by the paramedics who arrived and were able to restore a heartbeat."
Pegula's mom has been the co-owner of the Bills since 2014, when she purchased the franchise with her husband, Terry, for more than $1 billion.
The pair also own the NHL's Buffalo Sabres, making Kim the first woman to become president of both an NFL and NHL team.