Jessica Pegula has been wearing a number three on her outfit at the Australian Open, and she confirmed it is to show support to Damar Hamlin.

Buffalo Bills safety Hamlin went into cardiac arrest during the game against the Cincinnati Bengals on January 2 and spent over a week in hospital, much of that time in critical condition.

Pegula's parents own the NFL franchise as well as the Buffalo Sabres NHL team, and during her second-round win over Aliaksandra Sasnovich in Melbourne, was seen with a number three on her skirt, which is Hamlin's number and became a symbol of appreciation from well-wishers during his recovery.

"I definitely wanted to do something," Pegula said after her 6-2 7-6 (7-5) victory over Sasnovich. "We were kind of figuring out what the Bills and the Sabres were doing, just as far as what was the message.

"I knew they would probably do something and what message were they trying to send. It ended up being [that] the three was the symbol.

“I just thought it would be cool to put on my outfit here. I thought it would be a fun way to kind of connect with the team and then also just show my support."

There had been speculation that the number was related to her ranking, with the 28-year-old coincidentally the WTA world number three heading into the Australian Open, where she is the third seed, but Pegula laughed off the suggestion.

"I saw someone tweet that: 'Why would you put your ranking on your skirt?'. I'm, like, 'No, that’s not why,'" she said with amusement.

Pegula will play the winner of Olivia Gadecki and Marta Kostyuk in round three at Melbourne Park.