DALLAS When you devote your career to winning the final game, what do you do after it’s been won? At long last Dirk Nowitzki didn’t know what he was in for."I didn’t know what to expect,” he said Monday night, eight months after he won the NBA championship. The Mavericks’ locker room was almost empty following their routine 89-73 beating of the overmatched Celtics."I know one thing changed, and that was my motivation was gone for a little bit,” Nowitzki went on. "And I really had to fight to get it back and get the fun back.”His contributions of 24 points, 16 rebounds and two blocks had seemed almost routine. That he was able to acquire such numbers without strain was a victory in itself. He could not have made it look so easy one month ago. The problems he was having earlier this season could be traced back to the success of last June, when he and the Mavs finished off the Heat in Game 6 of the Finals. Nowitzki’s two big goals had been to win the NBA championship that for so long had remained out of reach, and to lead his country to an Olympics, which he accomplished while bearing the German flag during the 2008 Opening Ceremony in Beijing.Within weeks of winning the NBA title, he was back in the gym, training for the European Championship in hopes of qualifying for another Olympics. It was too much. He was overwhelmed."Now I reached both goals, and it was just hard in the beginning,” he said. "The Euros came too quick, right after the [NBA] championship. I only had, like, a month off. I needed more time to get away and enjoy the championship. If I would have had a couple months off to enjoy it, party, get everything out of the way, then start slowly back up -- that would have been the way to go. But I decided to play, to try my best, and we didn’t qualify, unfortunately.”They finished ninth, and part of him felt finished as well. He had always counted on playing out his current contract through 2013-14, when he will be 36. "For the first time really this year, I had a little doubt -- how long is this going to be going on?” he said. Like so many other older players, he wasn’t in condition when the season opened following a brief training camp. His knee was bothering him, and he was given time off by the team to recuperate and recover.In the meantime, the Western Conference coaches were voting Nowitzki to the All-Star Game for an 11th straight year. It was a vote of respect for what he accomplished, and it also put his momentary issues into perspective: Nowitzki’s rivals coaches were expressing certainty that he would recover both his drive and his health.At that point, Jason Terry, who was dressing in the neighboring stall, couldn’t listen to it anymore. "But when you’re a champion,” he interrupted firmly, "you get to go wherever the hell you want to go.”He wasn’t going to dwell on it either way. After his first couple of All-Star appearances, he quickly learned to consider the honor as a perk rather than as a goal. That view fit in with his larger sense of perspective, which in turn has earned the respect of so many i the NBA. After all of these years that led like a staircase toward the ultimate reward, the champion still wants to earn everything.His knee is stronger. His game is improving. His deep team ranks first in field-goal defense and may yet emerge as main a challenger to the top-seeded Thunder. Most important is Nowitzki’s renewed sense of ambition, because the entire mission would seem hopeless without it. "Now I’m as fiery as I ever was,” he said. "I’m out there moving well again and feel good.”Eight months later, he understands that the championship had one major impact."The only thing that changed is when I go home I see that massive ring that will be there for the rest of my life,” he said. "And that’s always sweet, every time I walk by in the house with a smile on my face.”