Keys produced arguably the finest performance of her career to win her very first Grand Slam title against the two-time defending champion.
This came after the American came up with another impressive display to defeat Iga Swiatek in the semi-finals via a final set 10-point tiebreak.
After beating Aryna Sabalenka, Keys became the oldest player to defeat the World number one and two in semi-finals and final at a Grand Slam event since WTA Ranking records began in 1975, and Pegula thinks she knows why.
In the Australian Open final, Keys opened up a 5-2 lead before taking the first set 6-3. Sabalenka bounced back in set two, before both players pushed each other to the wire in the decider.
This is the first women’s Grand Slam final to reach 5-5 in the third set since Serena Williams faced Victoria Azarenka at the 2012 US Open.
The set went with serve until the final game, when Keys broke Sabalenka while she served to stay in the match, which meant she won the Australian Open and made history in the process.
While speaking to reporters at Indian Wells, Pegula says she believes Keys’ wedding and a change in mindset helped her win the biggest title of her career.
“It was a really nice moment for her, especially post-wedding, being a newlywed and all these great things going on in her life,” Pegula said.
“I think she even said she kind of let go of the fact that she didn’t need to win a slam to feel like she had a successful tennis career. I think just being happy in her personal life probably really helped her get to that moment of winning a title.”
Keys’ Australian Open win is one of the most memorable moments in recent tennis history.
She has tried so hard to win one of tennis’ four prestigious titles throughout her career, and the 30-year-old has now joined the elite group of Grand Slam champions.
Pegula, who Keys beat to win the Adelaide International before heading to Melbourne, was delighted to see her friend attain the highest form of success in tennis.
“I think it was just a very nice, wholesome kind of inspiring moment, and it’s cool,” the World number four added.
“I think in women’s tennis we have a lot of those stories now where you see a lot of different stories and different journeys from different players.
“I think that’s what makes it so interesting. Hers was definitely a nice one to see and something different to kind of start the year.”