One day, two matches and a generation turned yesterday in Rotterdam. Yes, it's only a day in February on an indoor court, but yesterday in two matches, the tennis world took a seismic turn. Where were you, hitting groundies in Florida, watching your kid take a group lesson where they tried to change his backhand grip and service grip in 90 minutes when he's only 6, or checking out the Tennis Channel?If you missed it, here's what happened. First, Grigor Dimitrov knocked off Marcos Baghdatis. Now one would say, "Is beating Baghdatis really such an accomplishment these days?" The Cypriot--isn't it cool just saying that? The Cypriot--is ranked No. 37 now and he's clearly a nice player going nowhere. He's tried getting in shape, he's tried different coaches, he still hits a beautiful ball, but he's on the outskirts of the game today even as he beat Richard Gasquet before facing Dimitrov. Dimitrov has been the next big thing since he was 17 and his then-coach, Federer's former coach, Peter Lundgren, said the young Bulgarian was better than Roger at that age. Dimitrov has taken the last four years to hone his considerable talents and game. He is mini-Federer in a way that no other championship-level player has ever followed and imitated another champion players form. The only thing he doesn't have is Roger's air of a champion, the look of nonchalant superiority and "tough luck, buddy. Thanks for the workout," dismissal that Federer politely stiffs his opponents with.Well, that all changed yesterday. One day after Valentine's Day, when Sam Querrey was struggling to beat another so-so opponent in San Jose and Rafael Nadal went 6-4 in the third against a 30-year-old Argentinian ranked No. 78 in Sao Paolo, Dimitrov outclassed Baghdatis, whose a gateway player, you have to beat him to get to the top. And Federer, he amazingly lost to Julien Benneteau. Who, you say? Nicolas Mahut? No, not Mahut, even though Benneteau and Mahut seemingly are the same player, not in their form, but in their being just another good French player who never quite made it.Dimitrov is an inch taller and remarkably 22 pounds lighter than Fed, who comes in at 6-1, 187 pounds (who'd ever think the slight Fed with no muscle tone in his upper body would weigh 187 pounds?). That's how slight the Bulgarian is, but he smacks his groundies and displayed a stinging serve against Baghdatis. Dmitrov also showed an elasticity and an ability to sustain rallies that seem to eluding Federer now. This is where Fed seems to be showing the first full rust of his game. This springiness in movement and in snapping off aces in big moments. Fed's serve, even more than his grace around the court and his viper's tongue strokes, has always been his calling card and now with maybe the legs getting stiffer playing back to back days, he's not punishing his opponents as much with it. For Federer to lose to Benneteau, the 31-year-old Frenchman ranked No. 38 in Rotterdam, an older gateway player than Baghdatis, but still in that category, it might not be that big a deal. Benneteau had beaten him before indoors in Paris in 2009, but Federer usually knocks off unoriginal players like the Frenchman before he has breakfast. Maybe Fed's disdain for his opponents will lead to more losses in matches like this that are seemingly unimportant. But I think in one day, yesterday, you saw the changing of a generation with Dimitrov ascending and Roger starting the long last lap of a champion. I propose that you will see Dimitrov, who's ten years Fed's junior, maybe a generation-and-a-half younger than his model, win his first Slam before you see Roger win his 18th. And you may look back on February 15th, 2013 and say, "That's when the tides turned."