The last thing John Isner needs is a top-10 list to explain why he wishes to not be primarily remembered for winning the longest tennis match in history. Two reasons will suffice. 'I want to be a top-10 player and I want to win a Grand Slam tournament,' he said. In the past 14 months, Isner has made the climb from the world's 150th-ranked player to No. 19. But he knows that his current claim to fame is as the winner -- or survivor -- of a three-day, 11-hour-5-minute Wimbledon first-rounder that culminated last week with a can't-happen-but-did 70-68 fifth-set victory over Nicolas Mahut of France. So while the tournament continues across the Atlantic, Isner, after losing in the second round, has joined the New York celebrity studio circuit. On Monday, he visited the 'Late Show with David Letterman,' where he enjoyed sharing his top-10 thoughts during the exhausting and record-obliterating fifth set. No. 1 was, 'Larry King has had marriages that didn't last this long,' which perhaps means that Isner has one less appearance with which to concern himself. Crossover fame came so unexpectedly to Isner that it has not even had time to go to his head. After breakfast with a reporter Tuesday at a restaurant near his hotel on Central Park West, he offered to pick up the check. Isner will learn about the perks and protocol of a more lasting stardom, especially if he achieves the goals he has set. 'I think my best tennis is still three years ahead of me,' he said over a hearty plate of oatmeal, eggs, sausage and muffins. 'Physically, I'm fresh. Even though I'm 25, I don't have the wear and tear like all these guys who started at 18.' He laughed at the contradiction of the claim, made less than a week after he stumbled around the grass on Wimbledon's Court 18, 'punch drunk, to the point where I really wasn't aware of my surroundings, where the only thing that kept me going was trying to get to that changeover to sit down.' But therein lies the story's triumphant charm. A year ago, Isner could not even play Wimbledon because he was bedridden with mononucleosis. Going further back to when he was a scholarship player at Georgia, the notion of turning professional like the rest of the world's teenage prodigies was almost laughable because Isner was skinny as a rake and still adjusting to an unplanned life at an uncommon tennis altitude, 6 feet 9 inches. His parents, he said, are each a shade less than 6 feet. His older brothers are 6-3 and 6-4. Entering high school in Greensboro, N.C., Isner was 6-2, a top-10 junior player but also a skillful if undernourished forward in a competitive basketball environment. 'I got bounced around because I was so skinny, but I was a pretty good player,' he said. 'I just knew if I wanted to get a college scholarship, I had to focus on one sport, so I chose tennis. 'Then I grew six inches after I turned 17. I had no idea I was going to be this tall. Had I known that, I honestly would have stuck to basketball.' Since Isner made his debut on the ATP tour in the summer of 2007 with a resounding run to the finals of a tournament in Washington, there has never been a question that he had the serve and forehand to blow an opponent off the court. But at his height, did he have the ability to stay on it against smaller, more athletic opponents? Conditioning and movement will always be the most daunting challenge for a player his size. Isner, in fact, skipped the pre-Wimbledon grass-court tournaments because he was drained by the clay-court season and decided he was better off putting in more work in the gym. Still, Mahut was the fresher player throughout their ordeal. Asked for the most surprising moment of the match, Isner cited Mahut's all-out sprint and futile stretch dive for a volley Isner had punched into the open court. 'At that point, all I could do was chuckle, him risking life and limb like that,' Isner said. Isner said his fretting mother, Karen, and others in his box -- including his college roommate and teammate, an Australian Serb named Stracky Bobusic -- should have known he was not going to quit, no matter how wobbled he was. 'My family and friends, they know that I'm a really good competitor,' he said. Isner actually woke up last Friday thinking he could play his second-round match at noon and then meet a doubles draw commitment. Reality set in early; he was too sore to walk to the practice courts for a warm-up before losing in straight sets to Thiemo de Bakker. Five rounds from the final, Isner left London believing his amazing demonstration of resolve had moved him closer to his ultimate destination, a Grand Slam winner's circle. 'Prior to that match, I was a nobody at Wimbledon,' he said. 'Now I think people know what I have inside me.' The tall young man people used to mistake for the basketball player he might have been has been getting the once-over since last week and the question, 'Are you that guy?' He is the guy, not yet in the top 10 but with more reason to believe he will be there soon. 