(racket popping) - One thing I love about Serena is that she not only won 23 Grand Slams single titles, she did that while staying loyal to who she was, to staying loyal to her vision, and breaking barriers and stigmas about women in sports.

- [Billie Jean King] There are hundreds of different moments we can choose from in Serena Williams' prolific career.

One thing that stands out to me is the "Serena Slam."

(racket popping) Serena burst into the tennis scene as a rising star after her first women's singles championship at the US Open in 1999.

But by 2002, two and a half years had passed with a series of quarterfinal exits, and Serena was not meeting expectations.

Then at the French Open in June 2002, Serena defeated the top seed, Jennifer Capriati, in the semifinals.

She advanced to the next round, going head to head with her legendary sister, Venus Williams.

The match displayed Serena's strength, speed, and unwavering talent.

The press and the spectators went wild for these two incredible sisters fighting it out on the court.

In straight sets, Serena came out the champion of the 2002 French Open.

She quickly turned her focus to Wimbledon and the US Open.

Both Grand Slam tournaments had been a lifelong dream of hers.

In each championship, Serena and Venus played against one another.

But each time, the younger Williams sister won the match in the finals in straight sets.

In 2003, Serena Williams arrived in Melbourne as the reigning champion.

But would she be able to take her fourth consecutive major title at the Australian Open?

After coming close to an early upset with Émilie Loit, Serena sailed through, until she met Belgium's Kim Clijsters in the semifinals.

In the third set, Serena was down 5-1 but miraculously turned the match around and defeated Kim Clijsters.

Once again, Serena faced Venus.

The sisters battled it out for a grueling two and a half hours, and Serena had to fight harder than ever.

This was not going to be a straight-set match.

Serena took the first set, but Venus came back with a powerful serve to win the second.

Serena prevailed at the end, making her the Australian Open champion.

Not only did she emerge from her older sister's shadow, she achieved the "Serena Slam," winning four Grand Slam titles in a row.

Serena went on to achieve what is now known as the "Serena Slam" once more in her career in 2015.

- To see how strong she was, to see how committed she was for the game, how passionate she is about it, gave me the strength and the confidence I needed.

I immediately felt engaged with her.

I felt her passion.

I felt her fire inside for the sport.

I'm inspired with her career and everything she has done.