Except Isner is not a low ranked player. He's no 23 in the world. Granted, his biggest weapon is his huge serve and this is his main advantage. I don't think al

Except Isner is not a low ranked player. He's no 23 in the world. Granted, his biggest weapon is his huge serve and this is his main advantage. I don't think all of the top players are as versatile as you propose. Even "versatile" players fall back to their strengths when they go through these five set marathon matches. Look no further than the 2008 Wimbeldon final where Nadal battled Federer for almost 5 hours and eeked out the fifth set 9-7. At the time, commentators were claiming this to be the greatest tennis match ever.