Yes, Lendl was a tough matchup for anyone, but no, PC1, that's not what I was thinking in my earlier post. I think I was just wrong in thinking that Mecir had a favorable head to head record vs. Lendl AND McEnroe. It's probably ONLY against McEnroe, and NOT Lendl.
I WAS thinking that Mecir actually BEAT Lendl the majority of the time, but though Mecir used to play Lendl tough, I could be wrong about that. It just seems that Mecir's range/size, movement/fitness could neutralize Lendl's power baseline game well, but I need to check their head to head record and look at their results more closely.
McEnroe HATED to play Mecir. I do see a web posting about Mecir upsetting Lendl in 1987. Perhaps that was the Key Biscayne upset that poster Urban was mentioning above. Yet, he got killed by Lendl in the 1989 AO Final, so perhaps the 1987 match was an anomalous match between them.
http://en.wikipedia.org/wiki/Miloslav_Mečíř (wikipedia on Mecir)
http://www.youtube.com/watch?v=ae7lyHnuOdw (1987 WCT Finals vs. McEnroe, Mecir won easily 6–0, 3–6, 6–2, 6–2, but McEnroe played very little that year in total)