**If** your tennis-player is Paul, then his proper name was Paul Herz Ritter von Hertenried. His father was the Jewish railway engineer Julius Herz (1825-1910), elevated to the nobility as Ritter von Hertenried.
Paul was born in Vienna on 15 March 1859 and died at half past midnight on 23 March 1908 "after long and painful suffering" at the age of 49.
Paul's obituary notice in Neue Freie Presse of 24 March 1908:
http://anno.onb.ac.at/cgi-content/anno?apm=0&aid=nfp&datum=19080324&seite=25&zoom=2(No mention of tennis, unfortunately!)
His father's obituary notice on 12 August 1910:
http://anno.onb.ac.at/cgi-content/anno?apm=0&aid=nfp&datum=19100812&seite=17&zoom=2He married Anna Isabella von Ephrussi (b.1859), daughter of the Russian-Jewish Viennese banker Ignaz von Ephrussi (1829-1899). Not sure when they married, but I suspect it was 1889, when Anna converted to Christianity. (Some "sources" erroneously give 1889 as her year of death, but she was clearly still alive when her husband's obituary was published in 1908!) Paul appears to have converted in 1882. They had two children: Dominik and Paulette, who married Baron Franz von Pidoli
You may be able to find more information in "Wer einmal war: Das jüdische Großbürgertum Wiens 1800-1938" (vol.1: A-K), by Georg Gaugusch, published in 2011 by Amalthea Verlag, ISBN 978-3850027502. Paul is certainly mentioned, according to the indices available, but it ain't cheap!!
Adrian
P.S. The above info was gleaned from the databases at genteam.at