Floyd Mayweather (L) of the U.S. punches Tenshin Nasukawa as the American boxer beat the Japanese by a technical knockout after just two minutes of a New Year's Eve bout in Saitama, Japan, December 31, 2018. /VCG Photo

Serena Williams (L) of the U.S. and Roger Federer of Switzerland take a selfie after their historic first mixed doubles match at the Hopman Cup in Perth, Australia, January 1, 2019. /VCG Photo

Michael van Gerwen of the Netherlands throws during the final match of the PDC World Darts Championship, which he won to land his third title at the event, in London, UK, January 1, 2019. /VCG Photo

Norway's Ingvild Flugstad celebrates after winning the ladies' 10 km mass start event at the FIS Cross-Country World Cup in Oberstdorf, Germany, January 2, 2019. /VCG Photo

Houston Rockets players congratulate James Harden (C), who scored a game-high 44 points during their NBA matchup against the Golden State Warriors in Oakland, California, U.S., January 3, 2019. /VCG Photo

Serbia's Novak Djokovic reacts as he suffered a surprising loss against Roberto Bautista of Spain at the ATP Qatar Open in Doha, Qatar, January 4, 2019. /VCG Photo

Australian cyclist Rebecca Wiasak (L) celebrates her win at the 2019 Road National Championships Women's Elite Criterium in Ballarat, Australia, January 4, 2019. /VCG Photo

China's tennis players Peng Shuai (R) and Yang Zhaoxuan jointly lift the trophy after winning the women's doubles match at the WTA Shenzhen Open in Shenzhen, south China's Guangdong Province, January 5, 2019. /VCG Photo

Players of Bahrain celebrate their first goal during their opener match against the UAE at the AFC Asian Cup, which ended in a 1-1 draw in Abu Dhabi, UAE, January 5, 2019. /VCG Photo

Peru's Lucas Barron (L), the first co-driver with Down Syndrome, takes part in the Dakar Rally next to his father and driver Jaques Barron (R) at the Dakar Rally in Lima, Peru, January 6, 2019. /VCG Photo