As well as delpo played in 2009, he still should not have won the us open where he played out o his mind against federer who didn't go up 2 sets to 0 as he should have. Anyways, federer plays delpo differnt now than just trying to out hit him. He plays more variety, brings him to net, goes to net himself, and is always mixing it up. I believe delpo is back in fact his movment has improved from what it used to be. You'll see when he beats a top 4 player in the next events at dubai, indian wells, miami.
The "real Big Four" isn't back. del Potro wasn't even much of a challenge for Federer. Once he finally beats one of these guys, then maybe the talk can start - and even then there's not much to say given his horrible head-to-head against Federer, Djokovic and Murray. Beating up on Berdych and Soderling (which delPo did last year) is not the same thing.
Andy Murray: 2012 Olympic gold and silver medalist. US Open Champ. Wimbledon champ. Never been prouder of him.
The Brian Baker Story. Proof that truth is stranger than fiction... until Hollywood buys the rights and proceeds to keep screwing the script up.
delpo loss to federer says nothing about the other 3. Delpo doesn't like the way federer plays him. Delpo likes the games of nole and nadal much better and will push them and may even win if they meet at the us open or at indian well/miami... you'll see.
Del Po doesn't like variety. Coincidentally his H2H worst record percentage-wise just happens to be against Murray.