The Williamses' personal playground

WIMBLEDON, England -- Can Roger Federer, beginning play Monday, win his record-equaling seventh title here?

Will Rafael Nadal become the third man in three years to complete the arduous Roland Garros-Wimbledon double -- after more than a quarter century with no man achieving it?

After a four-year and three-year hiatus from the All England Club, respectively, how will Kim Clijsters and Justine Henin fare? Is Maria Sharapova's tender shoulder again ready for prime time?

Maybe the most compelling storyline here -- the longest-running, too -- is so obvious that people are just missing it: Will the Williams sisters continue to make Wimbledon their personal playground? The bigger upset would be if they didn't.

During the past decade, either Venus or Serena has won the title eight times. Only Sharapova (beating Serena in the final in 2004) and Amelie Mauresmo (beating Henin in 2006) have broken the Williamses' death grip on the event. Venus has five titles, including two of the past three, and Serena is a three-time -- and defending -- champion.

This year, Serena is seeded No. 1, with Venus No. 2. If they both reach the final, it would be the fifth all-Williams final and the third in a row.

"We're here to work, and we're here to do our best," Serena said on Sunday. "Hopefully, that's taking home a title.

"What enjoyment we get out of it is just the satisfaction of working hard and seeing the fruitage of that."

Or something like that.

The bottom half of the women's draw opens play Monday, so it will be Venus in action first, facing Rossana De Los Rios of Paraguay. Serena will be scheduled to play Tuesday -- against the yowling Michelle Larcher de Brito -- and, with a win (she is 42-0 in first-round matches in the majors), could gain an audience with the Queen of England.

Yes, Queen Elizabeth II will be on hand Thursday for the first time since 1977, her silver jubilee year, and already there is much talk of protocol. Officially, since 2003, players here have not been required to bow or curtsy to royalty, and the 84-year-old monarch has made it clear she will not insist players do so now. The All England Club, however, will ask players ahead of time which they intend to do.

"She hasn't been to this tournament in just forever," Serena said. "I thought, 'Wow, I've just got to make sure I'm here on Thursday.'"

And the curtsy?

"I've been working on my curtsy," she said. "It's a little extreme, so I'm going to have to tone it down. I have a lot of arm movement. I get really low."

Because she is seeded No. 16, Sharapova could run into Serena in the fourth round. After winning in 2004, Sharapova reached the semifinals the next two years. She hasn't won more than three matches since, but her recent results -- and a soft draw (No. 9 seed Daniela Hantuchova is her toughest potential opponent through three rounds) -- suggest she might keep her fourth-round date with Serena.

"She's a really hard worker, and her attitude on the court is definitely carried off the court of never giving up, always fighting," Serena said. "It's not easy to come back from any type of surgery. She is clearly doing well."

The Belgians, too, could meet in the fourth round; the winner of the No. 8 seed Clijsters and No. 17 seed Henin match could produce Venus' opponent in the semifinals. Wimbledon is the only Grand Slam event Henin has yet to win.

"It's cool they're back in the draw," Serena said, "It's fine. I answer this question every week, so look at my other transcripts."

Serena will turn 29 in September, while Venus hit 30 last week. It doesn't seem possible -- especially when you see the photos of young Venus winning here a decade ago -- but this is Venus' 50th Grand Slam event.

To put the Williams sisters' dominance another way, consider their 19 combined Grand Slam singles titles. The rest of the field -- including freshly minted French Open champion Francesca Schiavone -- has 16.

Now that's a story.

Greg Garber is a senior writer for ESPN.com.