Team Bethanie Mattek-Sands/Lucie Safarova: "Great start in WTA Finals with a doubs win over Muguruza/ Suarez Navarro!"

PHOTO: INSTAGRAM/LUCIE.SAFAROVA

Spotted in the WTA fan zone's Grand Splat booth: "Alicia Nur getting her first taste of tennis at just 18 months."

PHOTO: INSTAGRAM.COM/TENNISFOREVERYCHILD

Above: Singapore high jumper Michelle Sng (left) and waterskiier Sasha Christian: "Can't wait to watch the match between Sharapova and Radwanska!"

PHOTO: INSTAGRAM/MICHSNG

WTA Finals emcee Andrew Krasny: "Let the games begin."

PHOTO: TWITTER/ANDREWKRASNY

"I am happy to hear you want to go back to business @serenawilliams. Je suis pret."

- Coach Patrick Mouratoglou's response to world No. 1 Serena Williams' question on Instagram: Tu es pret? (Are you ready?)