Juan Carlos Ferrero is certainly not a breakout player anymore but since his ranking has sunk below the 100s, he is qualified for this award, which I give to the lowest ranked player to reach the fourth round of the Grand Slam - and it can include players on the comeback trail - like JC.
Unfortunately, JC lost to Janko Tipsarevic 57 76(3) 57 26 and failed a quarterfinal bid. He had wins though over compatriots Marcel Granollers (#32) and Pablo Andujar (#45) an epic victory over Gael Monfils (#7) in the second round 76(5) 57 67(5) 64 64.
His fourth round appearance here should propel him back into the Top 100 again next week.