Editor's note: On Dec. 9, we began our 10-part year-end awards series. Stay tuned each weekday for our latest entry.
The toughest part about assessing Serena Williams' season is selecting the most remarkable achievement. Among the contenders:
• Becoming the oldest No. 1 in WTA history at 32 years old
• Winning 78 matches this season, 20 more than her previous best
• Going on a 34 match-winning streak, her personal best
• Winning two Grand Slams to extend her total to 17 majors, fourth on the all-time list
• Winning 11 titles, three more than her previous best of eight in 2002
• Taking a record $12.4 million in prize money, well above the previous high of $7.2 million won by Victoria Azarenka last year
Perhaps it's the combination of it all, that she's playing more and winning more than she ever has before. Though Williams won five of six Grand Slams between 2002 and 2003, until about 24 months ago she had rarely played a full schedule. Nearly a third of her 57 career titles have been won during that most recent span.
"Every tournament I play, I play to win. Not that I didn't do that before, but it was just different," Williams said, explaining what has changed. "And more than anything I enjoy playing tennis. I love being out there.
"I think maybe that makes a difference."
Williams' desire seems to have increased after she experienced serious health complications from a cut on her foot in 2010 and was off the tour for almost a year. After some mixed results initially, her form improved after she changed her racket strings in April last year and, following a first-round loss at the French Open, began working with coach Patrick Mouratoglou. She has been on a tear since then, going 124-6 overall with a 78-4 record for this season.
If there is any shortcoming to that run, it was that two of this year's four losses came at Grand Slams -- one an injury-affected defeat to Sloane Stephens, the other a loss to Sabine Lisicki at Wimbledon after being a break up in the third set. Though she has been affected by nerves on big occasions recently, that was one of the few times she has been overcome by them.
The other two defeats were to Azarenka, the player who came closest to giving Williams any semblance of competition this year.
There were, however, a few controversies off the court. In an interview with ESPN The Magazine, Stephens related how Williams, previously friendly with the younger American, had cut off contact after losing to her at the Australian Open. Stephens clearly regretted the remarks later, while Williams refused to be drawn into the episode.
Later, it was Williams who made news with comments in a Rolling Stone story, including an overheard phone conversation when she allegedly made disparaging remarks about Maria Sharapova and boyfriend Grigor Dimitrov. Sharapova made big headlines when she hit back during her pre-Wimbledon news conference, referring pointedly to Williams' rumored relationship with her coach.
Williams has responded by being very circumspect in her interviews, generally maintaining a positive, complimentary tone while discussing herself with restrained modesty.
On the court, her serving, consistency and variety may be better than ever. A full 14 years after winning her first Grand Slam and 10 years after her 'Serena Slam,' Williams is still setting the standard for the rest of the field.
Her ability to win big events was well-recognized, but she is now showing that she can dominate week in and week out, and stay around long enough to accumulate big numbers as well.
And that makes her not just the player of the year, but one of the greatest players in history.