Did Jürgen Melzer ever reach a world No. 1 ranking in doubles?
Yes
No
This information is not known
It's a secret
Answer
No, Jürgen Melzer never reached a world No. 1 ranking in doubles. His highest doubles ranking was World No. 2, which he reached in March 2009. He won the French Open men's doubles title in 2010 and the US Open men's doubles title in 2011.