Sixth seed Serena Williams battled sluggish conditions to defeat fellow American Kristie Ahn 7-6(2) 6-0 to begin her French Open campaign on Monday. Playing an opponent she beat in straight sets at the same stage at the U.S. Open less than a month ago, Serena Williams found herself struggling to win points on Court Philippe-Chatrier where the roof was opened just before the match. Williams started with three aces to win her opening game but the 102nd-ranked Ahn started moving better and chased down her opponent`s heavy groundstrokes, which on most surfaces would have ended up as winners.
Ahn, who was making her main-draw debut at Roland Garros, went up 3-1 and served for the set at 5-4 but the 39-year-old Williams rallied each time to force a tiebreaker. Williams, who has won three of her 23 Grand Slam singles titles at Roland Garros, raised her level in the tiebreaker…