![TENNIS on Twitter: "Nicolas Kiefer shares an epic #ThrowbackThursday photo of a very young, long-haired Federer, Haas and more: https://t.co/SmCb7RuuBI https://t.co/35jIpPBxHt" / Twitter TENNIS on Twitter: "Nicolas Kiefer shares an epic #ThrowbackThursday photo of a very young, long-haired Federer, Haas and more: https://t.co/SmCb7RuuBI https://t.co/35jIpPBxHt" / Twitter](https://pbs.twimg.com/media/DgPToHxUcAE-MV1.jpg:large)
TENNIS on Twitter: "Nicolas Kiefer shares an epic #ThrowbackThursday photo of a very young, long-haired Federer, Haas and more: https://t.co/SmCb7RuuBI https://t.co/35jIpPBxHt" / Twitter
![Nicolas Kiefer at the Los Angeles Tennis Open Editorial Stock Image - Image of wide, professional: 11418909 Nicolas Kiefer at the Los Angeles Tennis Open Editorial Stock Image - Image of wide, professional: 11418909](https://thumbs.dreamstime.com/z/nicolas-kiefer-los-angeles-tennis-open-11418909.jpg)
Nicolas Kiefer at the Los Angeles Tennis Open Editorial Stock Image - Image of wide, professional: 11418909
![Kiefer criticizes Zverev and Thiem: "Questioning whether they have anything other than tennis balls in their heads · tennisnet.com Kiefer criticizes Zverev and Thiem: "Questioning whether they have anything other than tennis balls in their heads · tennisnet.com](https://www.tennisnet.com/fileadmin/_processed_/d/1/csm_nicolas-kiefer_0ba1ca58f3.jpg)
Kiefer criticizes Zverev and Thiem: "Questioning whether they have anything other than tennis balls in their heads · tennisnet.com
![German tennis pro Nicolas Kiefer looks frustrated during his match against Belarusian Mirnyi at the ATP German Masters in Hamburg, Germany, Wednesday, 17 May 2006. Kiefer lost the match in two sets German tennis pro Nicolas Kiefer looks frustrated during his match against Belarusian Mirnyi at the ATP German Masters in Hamburg, Germany, Wednesday, 17 May 2006. Kiefer lost the match in two sets](https://c8.alamy.com/comp/D3NHRG/german-tennis-pro-nicolas-kiefer-looks-frustrated-during-his-match-D3NHRG.jpg)
German tennis pro Nicolas Kiefer looks frustrated during his match against Belarusian Mirnyi at the ATP German Masters in Hamburg, Germany, Wednesday, 17 May 2006. Kiefer lost the match in two sets
![Pro Tennis Player Nicolas Kiefer at the Los Angele Editorial Photo - Image of athletics, returning: 11418946 Pro Tennis Player Nicolas Kiefer at the Los Angele Editorial Photo - Image of athletics, returning: 11418946](https://thumbs.dreamstime.com/z/pro-tennis-player-nicolas-kiefer-los-angele-11418946.jpg)