Anything you try to do, he potentially has an answer for,...

Anything you try to do, he potentially has an answer for, ... He plays the game in a way I haven't seen before. I mean, he's the only guy where you hold serve for 1-0, and you're thinking, 'All right ... good (laughter).' That's how it is. You've always got that sense of urgency. It's an incredible challenge.