When did the youngest US Open men's singles champion in history retire?
2002
2018
2018
2018
2016
2018
2013
2016
2018
2013
2016
2018
2013
2017
2016
2018
2013
2009
2017
2016
2018
2013
2008
2009
2017
2016
2018
2011
2015
2013
2008
2009
2014
2017
2016
1912
2010
2018
2011
2015
2013
1913
2008
2009
2014
2017
2016
1924
2010
2018
1912
2011
2015
2013
2008
2009
2014
2017
1913
2016
2010
1931
2018
2011
1924
2015
2002
2013
1927
1912
2008
2009
2014
2017
2016
2010
2018
1913
2011
2015
2002
2013
1931
2006
2008
2009
1924
1921
2014
1905
1927
2017
2016
1912
1988
2010
2018
1909
2011
2015
2002
2013
2000
2006
2012
1913
2005
2008
2009
2014
1931
2017
2016
1924
1988
1921
2010
1905
2004
2018
1927
1912
2011
2015
2002
2013
1923
2000
2006
2012
2005
2008
2009
2014
2017
1913
2016
1915
1988
2010
1931
2004
2018
1908
2011
1924
2015
2002
2013
1939
1927
2000
2006
2012
2005
1912
2008
2009
2014
2017
2016
1909
1921
1905
2004
1913
1931
1924
1927
1912
1915
1923
1908
1913
1931
1907
1924
1939
1912
1909
1921
1927
1913
1924
1905
1912
1932
1913
1922
1915
1931
1923
1908
1912
1924
1907
1921
1939
1927
1896
August 2018