Dooku and Luminara Quote

Can someone provide me with the quote / source that states Luminara is a challenge to Dooku in combat?

Pretty sure it's just the opinion of some unnamed Jedi.. padawans even. I'm not aware of a credible/out of universe source saying anything about Luminara in relation to Dooku.

I thought it was out-of-universe tbh.

http://www.killermovies.com/forums/showthread.php?s=&threadid=606401&from=thread&pagenumber=1#post15491468