3. Half of success is what you do for yourself; the rest is what you do for others. Argue all you want about whether Williams' personal trophy case makes her deserving of the mantle of "best ever"; this U.S. Open title makes 17 career major singles titles for her career, Roger Federer numbers. But when it comes to paying it forward, she is the Jackie Robinson for women of color in this sport (with a major assist to big sister Venus). Consider the crop of talent sprouting behind her: 18-year-old Madison Keys, a Williams sisters fan as a tyke, reached the second round of the U.S. Open last year and beat Serena on the World Team Tennis circuit as a 15-year-old. Victoria Duval, 17, drew immediate comparisons to Williams after her U.S. Open first-round upset of Australia's Sam Stosur — the last woman to turn back Serena in a final in Queens. Taylor Townsend, an explosive 17-year-old who last year became the first American girl to hold the number one ranking in 30 years, called her meeting with Serena in 2011 "a dream come true." Tornado Black, the unseeded 15-year-old who came within a whisker of winning the U.S. Open juniors title, is following the Williams blueprint and going a way apart from the USTA. And then there's Sloane Stephens, a frenemy 'til the bitter end. On and on it goes. For those wondering how American tennis will survive after Williams retires, that's easy. Serena's legacy will keep it strong.