That's what the American tennis public wants to know. Is Mardy real? Sure he's performed well this year, quartering at Wimbledon, semis at Miami and finals of Canada. But do you know en route to his career-high No. 7 ranking and 33-16 record this year, he's only taken the scalps of two top-10 players: No. 6 David Ferrer in Miami and No. 7 Tomas Berdych at Wimby. There's been no great upsets of the Top 4 and with the exception of Del Potro in Miami Fish has been unable to beat any top players. At the Aussie Open, he went down second round to Robredo. Bad loss. At the French, third round to Simon. Not a good loss. Davis Cup in Austin, Tx, Fish went down to both Lopez and Ferrer, bad loss followed by an unexpected loss to a player he creamed earlier in season. So Fish has not proven by any stretch of the imagination that he is ready for a big breakthrough at the Open where he was rudely bounced by Djokovic last year in the Rd of 16 and by Nadal the year before in the quarters. Before the 2009 USO, Fish in eight USO's never progressed beyond the second round!Fish plays Nikolay Davydenko today in Cincy. The tall, lean, cool American, a young Clint Eastwood-looking chap, can learn something from Davydenko, who reached a career-high of No. 3 in 2006, but in 11 years of playing slams, has only reached the semis four times. Of course, Fish, who has only reached two slam quarters, would kill for Davy's slam record. Davy is now No. 31 and at 30 seems to be playing out his days on the tour. Fish at 29 is still presumably on the rise. But now he is a marked man, as Davy was last year after beating Federer and Nadal at the end of 2009. Unfortunately, Davydenko caved to the pressure, reaching the Aussie O quarters, missing the French because of injury and then getting knocked out of both Wimby 2010 and USO in second round.Is Fish wild or farmed? He's pulled out of next week's Winston Salem as is wise. Let former US No. 1 Roddick go south and play that new event. Fish has bigger fish to fry and we're going to find out mighty soon if he's up to the challenge.In the over-30 mix, Roger Federer seems to have cured his ills in one match last night against Del Po. If Federer can play this sharp, the old Roger, maybe there's still some fight in the old boy after all. And don't look now, but the man from Trumbull and Tampa, who used to have the edge on Mardy Fish and also once surpassed Roddick as the US No. 1, is playing better. In Cincy, he's set down Bagdhatis and Fognini. Is there one more big slam left in James and his Yankee J-Block at the Open?