"He's made me learn more from the losses that I've had than maybe I did in the past," he said of Lendl."He's always told me exactly what he thought. And in tennis, it's not always that easy to do in a player/coach relationship."The player is sometimes the one in charge. But he's been extremely honest with me. If I work hard, he's happy. If I don't, he's disappointed and he'll tell me."