Dominant Williams fearful of enemy within By Toby Davis LONDON (Reuters) - Based on form, Serena Williams is a stand-out favorite to win a second French Open title but her record at Roland Garros means she approaches the tournament with a touch of apprehension and fearful of the "lady in the mirror." Williams is world number one, unbeaten in 24 matches and has won four consecutive tournaments, yet she remains diffident after last year's debacle when she exited in the first round. It is 11 years since she tamed the Parisian dust for the first and only time in 2002 but such is her current dominance, coupled with recent claycourt successes, that it is hard to see beyond the powerhouse American. Last year's queen of the clay Maria Sharapova has already lost two 2013 finals to Williams while her hopes of laying down a marker in the last warm-up event in Rome were hit by illness. World number three Victoria Azarenka got one over Williams in Doha but was so comprehensively demolished by the American in the Rome final that she is likely to be nursing psychological scars that have little time to heal. Last year's semi-finalist Sam Stosur, with a high-kick serve and heavy top-spin ground strokes, has not been past the quarter-finals in any event this year, while 2011 champion Li Na has struggled in both the Madrid and Rome warm-ups. There is, however, one opponent who Williams fears could cause an upset - the enemy within. "Whoever I play is my opponent and also the lady in the mirror is the ultimate opponent for me and so (I have to be) cautious and go for every point," she said after swatting aside Azarenka 6-1 6-3 in Italy. Last year I was feeling excellent but didn't do great and this year I am cautious and I want to work hard and stay focused. I don't feel any pressure but in the past I have and, as I have always said, I have won every grand slam. Since creaking under the strain at last year's event, she has re-established her grip on the game that has delivered 15 grand-slam singles titles and more than $44 million in prize money. She won Wimbledon for the fifth time a month after capitulating in Paris and followed that with a fourth U.S. Open title. Her fearsome frame, ideally suited for punching holes through opponents on quicker surfaces, has often been considered a hindrance on the slippery clay which can demand a more graceful gait. In both Madrid and Rome, however, her imposing athleticism was unencumbered and her movement dynamic. Movement, and specifically the issue of keeping her lengthy limbs in check, was traditionally Maria Sharopova's problem at Roland Garros until last year. The leggy Russian once described herself as a 'cow on ice' on clay but there was nothing bovine about the way she went about claiming last year's title, dropping just one set on her way to lifting the Suzanne Lenglen Cup. Then it seemed she was on the verge of becoming the game's dominant force but that is now a distant memory after she failed to get beyond the semi-finals in the last three majors. A viral illness scuppered her chances of success in Rome where she was forced to pull out at the quarter-final stage before a repeat of last year's Roland Garros final against Sara Errani. Sharapova does not, however, expect it to have any bearing on her French Open condition. "It is one of those things and the body is not ready and with a bigger goal around the corner it's important to make the right and smart decisions," she said. I have (had) a lot of clay matches, so this is not lacking before the French Open. Australian Open champion Azarenka is the last person to defeat Williams back in February in Doha, if you discount the American's walkover defeat to Marion Bartoli in Dubai when she pulled out injured. The Belarussian, however, has never been past the quarter-final in Paris, a tournament that frequently forgets the seedings and allows specialist claycourters to flourish. Last year it was Errani who, though diminutive in stature, produced a series of canny tactical displays to battle her way to the final. This year the surprise will be if Williams once more loses the battle with herself.