Who has achieved a higher World Ranking (in either singles or doubles), Goran Ivanišević or Nenad Zimonjić?
Goran Ivanišević:  His career-high singles ranking was World No. 2 (behind Pete Sampras) in 1994. Nenad Zimonjić: Nenad Zimonjić (Serbian Cyrillic: , ] ; born June 4, 1976) is a Serbian professional tennis player who was ranked World No. 1 in 2008 in doubles. Nenad Zimonjić:  He is the second tennis doubles player from Serbia to hold the World No. 1, after Slobodan Živojinović.
Nenad Zimonjić