How often do you see Roger Federer losing track of the score? Watch his reaction after winning match point against Kei Nishikori in the 2014 Halle semi-finals. This year Federer is coming back in Halle as defending champion, trying to win his historical tenth title there. In 2017, he defeated the local hero and current world No. 3 Alexander Zverev in the final. In Halle next week, he will play his second grass-court event of the year after Stuttgart.