Alex O'Brien and Jonas Björkman both reached what World ranking in doubles?
Jonas Björkman Jonas Lars Björkman (] ; born 23 March 1972, Alvesta, Sweden) is a former World No. 4 Swedish professional tennis player. He is also a former World No. 1 in doubles. Björkman retired from professional tennis after competing at the 2008 Tennis Masters Cup Doubles championships.
Alex De Minaur Alex De Minaur (Spanish: "Álex de Miñaur" ; born 17 February 1999) is an Australian tennis player. He has a career-high ATP singles ranking of 184 achieved on 7 August 2017.