BFFs Serena Williams And Caroline Wozniacki Watch Mariah Carey’s Concert Before Match At The WTA Finals

Tennis pals Serena Williams and Caroline Wozniacki spent time together before their semifinals match in the season-ending tournament of women's tennis tour in Singapore. Williams and Wozniacki watched Mariah Carey's concert at the Singapore Indoor Stadium on Oct. 24.

Williams and Wozniacki shared snaps of their selfies at the concert on Instagram. They also had their pictures taken with the music diva.

"@Mariahcarey #Divas," Williams posted. "Best night ever, got to celebrate my win today at @mariahcarey's concert in Singapore, she was amazing," Wozniacki wrote on her account on the popular photo-sharing social media application.

Wozniacki also shared a video where Mariah was performing her hit single "We Belong Together." The Dane can also be heard singing in the background.

A day later, Williams and Wozniacki squared off in the semifinals of the WTA Finals. Wozniacki was ready to upset Williams, who smashed her racket after being down 5-2, in the first set. The Dane claimed the first set, but Williams fought back to win the second set, 6-3, and forced a decider.

Wozniacki was up 4-1 in the third set but failed to play well at crunch time. Williams won the crucial tie-breaker in the third set and advanced into the finals.

In an interview after the match, Williams said the semifinals match against her best pal was great albeit a difficult one. Williams felt that Wozniacki was the most deserving player to win after being undefeated after the group stages.

Williams defeated Simona Halep in the finale, 6-3, 6-0, and won her fifth WTA Finals trophy. The American avenged herself after her loss to the Romanian in the round-robin stage of the tournament. Williams and Halep previously played against each other on Oct. 22, and Halep came out the winner of the match, 6-0, 6-2.

Williams first won in the WTA Finals in 2001, after her opponent Lindsay Davenport failed to compete in the finals due to a knee injury. In 2009, Williams won her second WTA Finals trophy against her sister, Venus, whom she defeated in straight sets, 6-2, 7-6. Williams won again in 2012 through 2013 and successfully defended the title again this year.