All this talk about strong era, weak era, etc had me thinking who had the toughest competition when it comes to the greats of the sport. I think it's probably Ivan Lendl. He had a really strong generation preceding him, so it wasn't easy to break through (hence the lost finals), he had very strong contemporaries, and he had a very strong generation coming after him making it tough to win slams in his decline. He never had an easy period to clean up the slams. That's why his slam count isn't THAT high (considering his amount of slam finals and weeks at #1), if not he could have ended up somewhere between Borg and Sampras, depending on how much luck he had.