It was a day of celebration as the WTA Finals action commenced in Shenzhen while others were crowned as champions in Basel and Vienna. These are the Top 5 photos that sum up Sunday's action.
1. Roger Federer did not drop a single set on his way to capturing his 103rd career ATP title, and he got to do so in front of his home crowd. The Swiss star surged past Alex de Minaur, 6-2, 6-2, to hold up his 10th trophy in Basel. Federer joins Rafael Nadal, Novak Djokovic, and Daniil Medvedev in claiming four titles this season.
2. Naomi Osaka kicked things off in Shenzhen China on Sunday. The two-time Grand Slam champion starred in the sequel of her Australian Open final earlier this year against Petra Kvitova. Osaka was able to sneak past Kvitova 7-6 (1), 4-6, 6-4, to win her 11th consecutive match. Osaka claimed her last two tournaments in Beijing and Osaka and will look to take home one more trophy before the year closes.
3. Dominic Thiem got off to a slow start and struggled to control points in the first set, but once again was able to find his winning form. Thiem would go on to take the second set and post a 3-6, 6-4, 6-3 score against Diego Schwartzman to capture his first title in Vienna. The Austrian had the crowd on their feet with his spectacular shotmaking that ultimately led him to his fifth title of the season.
4. Purple group's Barbora Strycova and Hsieh Su-Wei started their doubles campaign in Shenzhen with a win. The two squeezed out a 6-4, 4-6, 10-5 victory against No. 5 seeds Samantha Stosur and Zhang Shuai on Sunday. The Wimbledon champions will next face Barbora Krejčíková and Kateřina Siniaková.
5. WTA Legend Ambassador Martina Hingis helped to kick off the WTA Finals alongside doubles World No. 8 Xu Yifan of China. Dancers, singers and a pianist opened the event with amazing performances before the on-court action commenced.