US Open could break age-old records

Adrees Latif | Reuters

Serena Williams chases down a return to Kiki Bertens of the Netherlands during their second round match at the U.S. Open Championships tennis tournament in New York, September 2, 2015.

Professional tennis is supposed to be a young person's sport.

But with leading contenders Roger Federer and Serena Williams well into their 30s, this U.S. Open could crown two of the oldest winners in the tournament's history.

Federer, a five-time winner who last hoisted the silver trophy in 2008, celebrated his 34th birthday on Aug 8. He entered this year's tournament seeded second after beating arch rival Novak Djokovic in a match in Cincinnati last month. That means Federer won't meet the top-seeded Djokovic unless and until they both make it to the final round.

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If he gets past Djokovic, Federer would be the third-oldest winner of a tennis major, after Australian Ken Rosewell—who won the 1972 Australian Open at age 37 years two months—and Spaniard Andres Gimeno, who won the 1972 French Open at 34 years, 10 months.

But even a win by Federer this year would be eclipsed by a victory by Williams, who will celebrate her 34th birthday on Sept. 26, just two weeks after the women's final match. That would give her a calendar Grand Slam; notching each of the four majors in a single calendar year.

Only three other women have done so: Germany's Steffi Graf in 1988; Australian Margaret Court in 1970, and American Maureen Connolly in 1953. An Open victory this year in Flushing Meadows will also earn Williams her 22nd major title win, matching Graf.

Comparing overall records for tennis players can be tricky, because rankings rely on an exceedingly complex point system maintained by the Women s Tennis Association and the Association of Tennis Professionals for men

The system has changed over the years, so simply adding up career points doesn't provide and apples-to-apples comparison. Yet the two organizations post their rankings weekly, so a comparison of those holding the top spot, week to week, offers a fair matchup over time.

By that measure, Williams' career stands out.

She has also landed in the top spot over a longer span of her career than any player in recent history, breaking into the top ranking in February 2002 at age 22.

But with long stretches at lower rankings, she has held the top spot for fewer weeks in her career than Graf, who was ranked first for 377 (nonconsecutive) weeks; followed by American Martina Navratilova (332 weeks), Federer (302) and American Pete Sampras (286).