Rafael Nadal's latest Barcelona title the most impressive of all

Top-seeded Rafael Nadal won his ninth title in Barcelona on Sunday with a solid 6-4, 7-5 win over No. 2 seed Kei Nishikori. As impressive and varied as the first eight efforts might have been, this one was a game-changer.

Nadal had been mired in a nasty slump since he won his last major title at the French Open in 2014. From then until earlier this month, he won just three titles -- none of them majors or even top-tier Masters events.

But Nadal's loss of form on his beloved clay had been most striking and, to many, most baffling.

Those vicious topspin forehand drives were not just falling short or flying wild; they suddenly seemed to lack the familiar sting and velocity. Nadal's eyebrows were perpetually furrowed. He walked as if the court were burning his soles and he sometimes spoke as if his brain were on fire, even as he fought off any urge to panic.

"If I don't win, I will think about the next tournament," Nadal said of his overall approach in his news conference after he lost to Djokovic at the French Open last year. "I will try to make progress. I feel competitive. I'm calmer on court. I don't have this problem of nerves that I suffered from at the start of the year, so we will attempt to move forward."

For 18 months, though, moving forward always entailed moving backward soon thereafter. Nadal never seemed to win enough matches to get over that critical hump and escape the vicious cycle in which confidence and anxiety chase each other like a dog chasing its tail. Successive titles on clay may help break that cycle.

For now, he's chugging into the critical month of May with back-to-back titles, one of them (Monte Carlo) a Masters crown. The wires in tennis are zinging and popping: The "King of Clay" is back, and he's still got his mojo.

Through most of his slump, we frequently saw flashes of vintage Nadal. These past weeks, in Monte Carlo and particularly in Barcelona, we watched vintage Nadal, albeit with flashes of his slump.

Make no mistake, he still makes the occasional, un-Nadal-like unforced error, and often at a critical time. Time and again in the Barcelona final, Nadal found himself behind his service games. It's admirable that he saved 10 break points, but it will worry his team that he offered Nishikori 13. Nishikori hit 29 winners, eight more than Nadal, although the Japanese star also made almost twice as many unforced errors (34-18), a detail that cost him the chance to win his third consecutive title at Barcelona.

Perhaps the best news for Nadal fans was an element that was not quantifiable on the stat sheet. Nadal seemed all-in and undistracted throughout the match. That sneering curl of the lip, those lusty groans of effort, all the ticks and the bombastic "Vamos" uppercut were all part of the repertoire in the final, which must have made Nadal feel that it was just like the old days.

But Nadal also knows you can't live in the past. He now has a week off to think about how to meet the future as he prepares for the great battles of May and the road to Roland Garros.