The study was to investigate the influence of stroke skills on winning/losing in tennis tournaments; more specifically, this study was to reveal which stroke skills effectively increase the chance of winning the tournaments. The subjects were the male players who advanced to the quarter finals in the 16-year-old and 18-year-old divisions in the 2012 New Taipei City Four-Pillars Cup Youth Tennis Championship. Correlation was used for data analysis. The results were as follows: the correlation between successful first serves and winning sets was .487; the correlation between forehand stroke and winning sets was .540; the correlation between backhand stroke and winning sets was .597, which were statistically significant at the level of .05. The study implies that players should strengthen these stroke skills when practice in order to help win the games.