![Roger Federer of Switzerland attends a training session ahead of 2019 Australian Open at Melbourne Park in Melbourne, Australia, on Jan. 8, 2019. Australian Open Tennis Tournament will take place from Jan. 14 to 27. (Xinhua/Bai Xue)](http://www.ecns.cn/hd/2019/01/09/1f4ae9e94b104fedb0cb6a40519cdc1d.jpg)
Roger Federer of Switzerland attends a training session ahead of 2019 Australian Open at Melbourne Park in Melbourne, Australia, on Jan. 8, 2019. Australian Open Tennis Tournament will take place from Jan. 14 to 27. (Xinhua/Bai Xue)
![Roger Federer of Switzerland attends a training session ahead of 2019 Australian Open at Melbourne Park in Melbourne, Australia, on Jan. 8, 2019. Australian Open Tennis Tournament will take place from Jan. 14 to 27. (Xinhua/Bai Xue)](http://www.ecns.cn/hd/2019/01/09/fe8b4b1b9b1b4aac8fa4d47588fd7393.jpg)
Roger Federer of Switzerland attends a training session ahead of 2019 Australian Open at Melbourne Park in Melbourne, Australia, on Jan. 8, 2019. Australian Open Tennis Tournament will take place from Jan. 14 to 27. (Xinhua/Bai Xue)
![Roger Federer of Switzerland attends a training session ahead of 2019 Australian Open at Melbourne Park in Melbourne, Australia, on Jan. 8, 2019. Australian Open Tennis Tournament will take place from Jan. 14 to 27. (Xinhua/Bai Xue)](http://www.ecns.cn/hd/2019/01/09/1252d8cfd51247c4b38fd1568d84e82e.jpg)
Roger Federer of Switzerland attends a training session ahead of 2019 Australian Open at Melbourne Park in Melbourne, Australia, on Jan. 8, 2019. Australian Open Tennis Tournament will take place from Jan. 14 to 27. (Xinhua/Bai Xue)
![Roger Federer of Switzerland attends a training session ahead of 2019 Australian Open at Melbourne Park in Melbourne, Australia, on Jan. 8, 2019. Australian Open Tennis Tournament will take place from Jan. 14 to 27. (Xinhua/Bai Xue)](http://www.ecns.cn/hd/2019/01/09/612d9777f0f34db7bace914a4ab71d37.jpg)
Roger Federer of Switzerland attends a training session ahead of 2019 Australian Open at Melbourne Park in Melbourne, Australia, on Jan. 8, 2019. Australian Open Tennis Tournament will take place from Jan. 14 to 27. (Xinhua/Bai Xue)