OF COURSE, ONE could take an alternative view: that struggling against a middling player was just a harbinger of the Next Great American's ongoing fade into mediocrity.

It's a reasonable sentiment. After bursting onto the global tennis scene with a nuclear serve (world-record speed: 155 miles per hour), a howitzer of a forehand, and a bombastic personality that charmed beat writers and agitated the competition, Roddick rocketed to No. 1 in the world rankings in 2003—then crashed into a wee bit of a brick wall in the form of Roger Federer, a.k.a. the Greatest Player in the History of the Sport. Over the ensuing four years, Roddick lost to Federer 15 of 16 times, including twice in the Wimbledon final. In the past several years, he's also fallen behind Nadal, the 22-year-old Spanish capri-pants enthusiast who dominates the French Open every year; and Djokovic, the lanky 21-year-old Serb who won the Australian Open in January. If you listened to critics—and there were many—Roddick had drifted into the second tier of top pros. He was an athletic player who could make a run at any given tournament but was destined to languish somewhere in the lower half of the top ten.

It seems funny to imagine that someday this trivia question might stump people: Who was the last player to hold the No. 1 ranking before Roger Federer's epic reign? The answer: Andy Roddick, then 21, now 25 and, despite rumors of his demise, very much still a force on the ATP Tour. Barring injury, he's got at least five years of elite tennis left in his body. While he's unlikely to take the throne back from Federer, Roddick clearly believes he's going to win more Grand Slam events. And he's probably right.

Here's what he says he was really thinking between those sets in Miami, when I was ready to stick a fork in him: "I lost a set 7-5. The guy played great. I served 35 percent first serves. So I was just thinking over stats and telling myself, You know what, this could turn quick, and when it does, it could go fast."

After dispatching his next two opponents, Czech Ivo Minar and Frenchman Julien Benneteau, to reach the quarterfinals, something momentous happened: Andy Roddick slew the dragon. He beat Roger Federer. And as he did in the match against Troicki, Roddick took some punches. He won the first set, then lost the second, and Federer entered the third in one of his bizarre zombie zones, in which he reels off points by the dozens, hitting shots that mystify and frustrate opponents.

Only this time Roddick hung in. "When he was hitting the shots, I would turn around and walk back [to the service line] and wouldn't do anything," he told me later. "I would just go to the next point. As simple as that sounds, that's literally what I was thinking. I got through a game with three or four break points and all of a sudden he actually froze. I think me actually staying the course gave him the opportunity to make mistakes."

When reporters swarmed the interview room to ask a very happy Roddick what had pleased him most about the match, the first thing he said was "I thought I stood the course mentally pretty well." Pressed to assess the significance of this quarterfinal match, Roddick said, "It's probably what's been missing the last two, three years."

Talk about an understatement.

Taking the long view, the win over Federer in Miami was a sort of tangible proof of something bigger: a slow rebirth that dates back to the Davis Cup title last December, the first for the U.S. since 1995. Entering 2008, Roddick won in San Jose, then won again in Dubai, beating both Nadal and Djokovic. Despite the stumble at the Pacific Life Open, he arrived in Miami feeling as sharp as he had in years. One reason became clear during the tournament, when news leaked that he'd gotten engaged to his girlfriend, the gorgeous blond Sports Illustrated swimsuit model Brooklyn Decker, 21, thus ending his tabloid-covered bachelor years, during which he'd dated, most prominently, Mandy Moore and (allegedly) Maria Sharapova. "I think being happy and content off the court is only going to help in my mind," he told reporters after the Federer match. Another boost came in the form of Federer suddenly appearing, if not vulnerable, then at least less invincible. He'd already stumbled in the early part of the season, losing to Djokovic and Scotsman Andy Murray, and in February he was diagnosed with mononucleosis. In Miami, Roddick would go on to lose in the semifinals to 27-year-old Nikolay Davydenko, but the Russian was by all accounts playing the best tennis of his career. Two days later, Davydenko absolutely smoked Nadal in the final.

"Roddick has matured a lot," says Davis Cup captain Patrick McEnroe. "He still has the same drive and intensity—he just seems more balanced. And that helps him in big matches. I think his chances [in Grand Slam events] are as good as they've been in years.

So Roddick heads into the meat of this season—to Wimbledon, the hard courts, and his home slam, the U.S. Open—with a new fiancée, a clear mind, and something even more significant: a giant Swiss monkey off his back.

"If I'm serving for a set next time, I'm not going to be thinking, Is this the time? God, please let this be the time," Roddick told me two weeks after his victory, the relief in his voice still palpable. "I think it'll be a little bit more straightforward."

Meaning you've had those thoughts before?

"I'd hope you'd call bullshit on me if I said, after losing 11 times in a row, I'm serving for match and that thought didn't creep into my head. That's why I said it was huge mentally for me in Miami."