Nguyễn Hoàng Thiên  Nguyễn Hoàng Thiên (born 12 March 1995) is a Vietnamese tennis player. Nguyễn has a career high ATP singles ranking of 1368 achieved on 18 June 2012. He also has a career high ATP doubles ranking of 773 achieved on 24 October 2016. Nguyễn represents Vietnam at the Davis Cup where he has a W/L record of 13–11.