Juan Martin del Potro's comeback from injury briefly stalled with a 6-2, 7-5 loss to Germany's Florian Mayer(Image) in the second round of the Sydney International Wednesday. After beating Feliciano Lopez in his comeback match in the first round Monday, the 2009 U.S. Open champion lost to the unseeded Mayer in 74 minutes. Del Potro dropped his serve three times in the match including, crucially, at 5-5 in the second set. Mayer said it was clear del Potro was not yet 100 percent after a wrist injury last year. "His serve is really strong but from the baseline he missed a lot," Mayer said. "I think also he was maybe a little bit tired from his long match Monday because when you don't play for such a long time and you play your first match over three hours, it's really tough. Read more: http://sports.espn.go.com/sports/tennis/news/story?id=6014157
