Five things we learned from Roddick's U.S. Open ouster

NEW YORK -- What we learned from Janko Tipsarevic's 3-6, 7-5, 6-3, 7-6 upset over Andy Roddick on Wednesday:

1. Roddick needs to turn back the clock. On Monday the top-ranked American turned 28, an age at which he wasn't expected to have much tennis left in the tank. But his late career surge is a credit to his adaptability. Tired of being dismissed as the two-trick pony with a blistering serve and big forehand, Roddick rounded out his game. He rebuilt his backhand, sharpened his reflexes at net and his improved his fitness. Since the retooling, Roddick has become a more serious Grand Slam challenger, one who came within a whisker of defeating Roger Federer at Wimbledon in 2009. Still, in Tipsarevic's estimation, what may be keeping Roddick from breaking through is that he no longer plays with the same abandon he did in his youth. "He needs to be more aggressive," Tipsarevic said. "People say he was much more dangerous when he was young because he was really going for the forehand every chance that he had. Now I just don't see that."

2. Roddick's gameplan failed him. The instructions he received from coach Larry Stefanki were simple -- keep the unforced errors down, make Tipsarevic take big swings from stretch positions and get a high percentage of serves in play -- and Roddick executed to a T. So why isn't he advancing in the draw? Because Tipsarevic countered Roddick's defensive approach with a relentless brand of high-risk tennis. "I kept telling myself, 'this has to have an expiration date on it," Roddick said. Tipsarevic said that maintaining that intensity will be his biggest challenge going forward. "The difference to become a champion in this sport is that you need to play this level not just for one tournament, but let's say for a period of a year, or in the case of [Rafael] Nadal and Federer just all year long."

3. The specter of Serena Williams is inescapable. First, it was her injury that kept her prominent on people's minds. Now it's her foot fault. Down 5-2 in third set, Roddick was called for stepping on the service line on his first serve attempt of the eighth game. When asked for clarification, the line judge told Roddick that his right foot had crossed the line -- a claim that subsequent television replays quickly proved untrue. (He did fault, but with his left foot.) Roddick blew his stack. He challenged umpire Erich Molina to name another instance his right foot had ever crossed his left on a serve, and the showed up the line judge by demonstrating the awkward form his serve would look if it did. The meltdown was effective in injecting Roddick's game with a bit of adrenaline, but not with enough juice for rally.

4. Mono was not a factor. Last month Roddick revealed that he had come down with a mild case of mononucleosis, and that the ailment had been at the heart of a few of his more sluggish showings earlier in the year. But on Wednesday he refused to use sickness as an excuse. "I feel fine," he said. "I feel like I'm gonna get some rest tomorrow."

5. Tipsarevic cannot blow this opportunity. The last time Tipsarevic beat Roddick at a major was the second round of Wimbledon in 2008, but Tipsarevic went on to lose to Germany's Rainer Schuettler in the Round of 16. As they shook hands across the net after the match Roddick told Tipsarevic he better not squander this opportunity. "Don't f---ing lose [this] time," he said.