Serena Williams called Tom Brady 'unbelievable' and said that the QB's success transcends the Patriots' system

• Serena Williams thinks Tom Brady is "unbelievable."
• After her first match at the 2021 Australian Open, she commented on the QB's Super Bowl LV victory.
• Williams implied that Brady's success belongs to him, not to his former team — the Patriots.

Serena Williams knows a thing or two - or 23 - about greatness.

And she thinks Tom Brady fits the bill.

The 23-time Grand Slam champion called Brady "unbelievable" after the 43-year-old quarterback led the Tampa Bay Buccaneers to victory in Super Bowl LV Sunday night. The win gave the Bucs their second Vince Lombardi Trophy as a franchise - and Brady his record seventh Super Bowl victory and fifth Super Bowl MVP award in his 21-year NFL career.

"It's unbelievable," Williams said from the Australian Open. "I just was watching [the Super Bowl] as much as I could to see. My only word is it's unbelievable. I kept saying this is unbelievable. This is unreal."

Safe to say Serena is a fan.

The tennis superstar is defying age in her own right. At 39 years old, Williams is ranked as the 11th singles player in the world and consistently torches opponents who are half her age. She said Brady "is in my age group" and that it's "exciting" to see him succeed well past the typical age of retirement in the NFL.

Williams also attributed the quarterback's success to him and only him, alluding to the discourse of whether Brady's career achievements were a product of his former team, the New England Patriots, and their longtime coach and general manager, Bill Belichick.

"You can't say it was the system he was at formerly," Williams said. "It's definitely Tom Brady. He's Tom Brady. He's amazing."

Williams cruised to victory in her opening match of the Australian Open on Sunday, besting Laura Siegemund 6-1, 6-1 to secure a second-round matchup against Serbian Nina Stojanović on Tuesday. Though Williams has already won the tournament seven times in her career, her eighth would mark a particularly significant milestone as she continues her chase of Margaret Court's record 24 Grand Slam titles.