Marat Safin might qualify. This is a guy that was so good, that he absolutely destroyed Sampras in the USO final. He also beat a peak Federer in the semis of the AO to eventually beat Hewitt in the 2005 AO championship. Safin has also been ranked #1 before.
And yet, Safin has been terrible at Wimbledon. Here is what Safin was ranked and what his result was at Wimbledon:
year world ranking result
2000 9 2nd round
2001 3 quarterfinal
2002 2 2nd round
2003 - missed Wimbledon
2004 15 1st round
2005 5 3rd round
Starting in 2006, Safin was ranked 24th or worse in the world while he entered Wimby. So I excluded those numbers since his overall play stunk anyway.
I.e, Safin was ranked in the top 10 at 4 different Wimbledons. His average result for these 4 Wimbledons in which he was ranked in the top ten was getting knocked out of the 3rd round. This is pathetic for a guy as good and as dangerous as Safin was.
