Yeah clay courters dont do as well on grass becoz ...clay is a skill leveller and grass is the polar opposite. The thing with Robredo , for me, he is 31 and has reached no5 in the world before. He can play a bit....and he has nothing to lose...He will come out swinging.
That said ive predicted Andy in 3 ....just a bit of caution bout this one tho.
Centre court, Andy, the crowd support for Andy, all can make him very nervous. He's done very well on clay this year especially at RG, but that's still clay and he'd played mostly against players of his caliber. He did not play a top player like Andy on grass so it's a whole different scenario for him. We'll find out I guess. He's a great competitor I'll give him that but how much can he display of that on his weakest surface like grass, that still remains to be seen. As to Andy, perhaps Robredo's competitive side will bring out the best in him. Andy loves playing on grass and especially at Wimbledon. It's ideal scenario for him. The contrast is significant.