ESPN Tennis

KEY BISCAYNE, Fla. -- Who knew that the Sony Ericsson Open would herald the introduction of a new character in men's tennis: Nikolay "Guitar Hero" Davydenko?

Two of the biggest questions going into the ATP season were whether Rafael Nadal would stay healthy, and whether Davydenko could continue to play at a high level even as the match-fixing investigation that catapulted him out of the shadows last August dragged into a new year.

Both men answered in Key Biscayne. The surprise was that Davydenko and his enchanted, 18-stringed Prince racket delivered a more emphatic response than the expressive Nadal, who played an injury-free early hard-court campaign but was beaten by the better man in the mini-season finale.

Davydenko was the most unsung player in the top 10 until the gambling issue reared its unattractive head. He climbed into the elite ranks by punching in every week and consistently playing his way deep into draws, but tended to fold against top guys in big matches, looking like the chess club president standing in against a star quarterback.

Personally, at least for the U.S. audience, Davydenko came across as Mr. Anonymous. His English is earnest but sketchy. Even his clothing sponsor, the French company Airness, is better known for dressing soccer players. Venerable tennis commentator Bud Collins said he's seen Davydenko crack jokes at public appearances, but that side remained well hidden on the court, to the point where reporters wondered if he enjoyed what he did for a living.

Davydenko's play didn't seem to suffer after the gambling story broke, and he did win the Kremlin Cup in Moscow last fall -- his only title of 2007. But by the time he showed up at the Davis Cup finals against the United States, he had a pale, hollow-cheeked, almost birdlike air. Although he was the top-ranked player on the Russian team, his horrible record against Andy Roddick and James Blake relegated him to playing doubles, where he looked tentative and dispirited.

Yet oddly, it was the pressure of the investigation that first gave us a hint about what might lie behind Davydenko's iron curtain. Far from going into hiding, he answered every question and successfully appealed an umpire's dubious "lack of effort" call against him.

Even so, few would have predicted Davydenko would make a career breakthrough in muggy Miami, displaying classic shotmaking, great footwork, speed and accuracy on his serve, and striking confidence along with his usual rechargeable-battery endurance. He looked tanned and relaxed. He smiled. He saved match points in his first-round matchup against Ernests Gulbis, then went on to upset two men he'd never beaten, Roddick and Nadal.

Davydenko kissed his racket after his shockingly lopsided victory over Nadal, and who wouldn't have? He wanted to experiment with more densely woven strings, and Prince supplied him with one sample of the model he requested. The fact that Davydenko was able to get through five matches without breaking a string is pure luck, but the wizardry he exhibited with those strings was not. It was a solo worthy of rock n' roll.

Nadal has now made two semis and a final in Miami the last three years, yet he is still questioned continually about his hard-court credentials and his serve. One of the things he tried to underscore here is that improvement on a given surface isn't always a linear process.

Six of his nine Masters Series championships were earned on clay in Monte Carlo and Rome -- the other three have come on hard court, two in late 2006 and one last year. Yet few people would dispute that Nadal is more versatile and formidable than he was two years ago.

"Always we must have the comparison," he said, politely but pointedly. "I think it's impossible [to] compare it. [In] 2005 I won in Montreal, I won in Madrid, I played the final here. The numbers are saying I'm not much better than 2005. I think I have more years, more experience. I'm better player than 2005. I don't have any doubt about this."

The questions Nadal gets have a sort of what-have-you-done-for-us-lately tone, which may be inevitable given his entrenchment in the No. 2 spot, going on three years now. He has handled the repetitiveness of that scrutiny with a lot of grace.

More Miami musings:

Hot feet: The Bryan brothers, exuberant after defending their Miami title to win their first championship of the year, chucked their sneakers and socks into the crowd after the match and arrived at their press conference barefoot. That momentum bodes well for what will not be a gimme against France in the Davis Cup quarterfinals next weekend.

Just a hunch: We think this could be the year Serena Williams is a bona fide competitor for the French Open title after being absent from the finals since 2002. The clay-court season certainly would be enlivened if she and Maria Sharapova both take it seriously.

Stealth Serb strikes again: At this time last year, Janko Tipsarevic had just tiptoed into the top 100. He hit a career-high No. 40 earlier this month and made an impressive run here, beating Fernando Verdasco, Thomas Johansson and the hard-headed Mikhail Youzhny in successive rounds before falling to the Davydenko juggernaut. Meanwhile, the Serbian hits just keep on coming -- 22-year-old qualifier Viktor Troicki, who gave Nadal more than he bargained for at the Australian Open, took Roddick to three sets in the second round.

Bonnie D. Ford covers tennis and Olympic sports for ESPN.com. She can be reached at bonniedford@aol.com.