Is Serena Williams the best of all-time?

Given the outpatient procedure that Serena Williams performed on Caroline Wozniacki Sunday, another surgical tennisotomy against another overmatched opponent, it is difficult to fathom how anyone else ever wins a women's Grand Slam event.

The mystery is that between Williams' first major title at the 1999 U.S. Open and this 18th Grand Slam trophy, 16 other women (including her sister Venus) have won a combined 43 majors. That includes all three previous Slams this year.

How can that be? Wozniacki was just the most recent example of a challenger unable to escape the Williams whirlpool of talent, helplessly sucked down in a 6-3, 6-3 defeat.

Williams often has argued that "I haven't lost many matches where the player was playing unbelievably good. Usually, when I lose, it's because I'm playing unbelievably bad."

The record bears her out. Especially in the Slams, which she has acknowledged are the tournaments she most cares about and the ones in which her own passion occasionally has cost her dearly. As in the foot-fault incident vs. Kim Clijsters in 2004 and the premature celebratory shout vs. Samantha Stosur in 2011.

At times, Patrick McEnroe said, Williams "has maybe gotten too uptight. She has to walk that fine line of being aggressive and being intense, but also trying to stay relaxed."

Wozniacki is a tireless retriever who keeps the ball in play and turns some defense into offense. But as Wozniacki observed, "Against Serena, you have to have a good start; otherwise, she starts going and being more aggressive. When she's on her game, it's not fun to play her."

In big Williams matches, a spectator's focus falls almost entirely on her: She will win a point with another powerful serve, another precise backhand, another cracking crosscourt forehand. She will lose a point if she aggressively misses wide or long. The opponent is just . . . there.

When readying to serve, Williams takes only one ball instead of the usual two, as if she is thoroughly confident she won't need a second serve. Though primarily a baseliner, she plays territorially, moving a step or two into the court as the rallies go on, ready to pounce.

Surrounded, Wozniacki hit exactly four winners in the match -- and three of them were aces. Williams pounded 29 winners and went for approximately 23 more (the number of unforced errors she was assessed while so often going for the lines).

As this year's Open played out, with seven of the top eight seeds (below Williams' No. 1) ousted before the quarterfinals, it surely was just a matter of time before Williams officially held her sixth U.S. championship trophy.

For years now, her tennis contemporaries have proclaimed Williams the greatest female player in the sport's history.

Some with more historic context might argue that Steffi Graf, who won 22 majors, could give Williams a good run for her money. Martina Navratilova and Chris Evert, each with 18 Slam titles, must be in the conversation, and possibly Margaret Court, whose 24 major trophies came in a different era.

To tennis historian Steve Flink, Williams "has to accomplish a bit more" before being anointed best ever. But despite turning 33 later this month, she does not appear to be in one of those long-way-to-go-and-short-time-to-get-there situations.

Barring injury or illness, she unquestionably will enter the 2015 Australian Open as the favorite. And probably Wimbledon 2015. And next year's Open.

Said Williams, "I'm already looking at No. 19."