I would have to say McEnroe, although tennis history is not exactly my forte.
If this counts, remember too that McEnroe's and Lendl's games were almost polar opposites of eachother, much like those of Sampras and Agassi. McEnroe was one of the best S&V'ers to play the game and had perhaps the best hands at the net, while Lendl pretty much pioneered the modern power baseline game.
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